You have several challenges ahead which are all surmountable, but will force you to perhaps work a little harder than the average applicant to top schools. For example, being Indian, male and from an IT background, you are already inside on of the largest of all applicant pools, so simply standing out amongst a throng of similar applicants is the goal. Here are some thoughts on your questions:
1.Should I work on shaping my extracurricular activities such that it meets the expectations of top notch colleges? You do seem a little light on extracurriculars. B-schools want to see that you are engaged with the communities in which you live and work, but with fall deadlines only a few months away, frankly anything you try to jump into now might come across as gratuitous fodder for the application. Having said that, I would look to engage in something that aligns with your interests or history or either something that wouldn't be so obviously "bolted on" here at the application period. For example, you could perhaps do something within your company that is community-oriented and outside your job duties, and it might seem as if you have been involved in it for awhile. I am not suggesting you fudge the truth, and if asked, you should certainly be forthcoming in how long you have been involved, but they may not ask. As for what you have already done, I would highlight the leadership component of your involvement, particularly the mentoring jumps out as well as the innovative nature of organizing a new activity like the Quiz. Business schools want to see some passion in all you do, so make passion your impetus. Being light on extracurriculars is only going to bring focus to the fact that you are young and don't have a ton of experience in general, both work wise and community wise. Try to emphasize the depth of your involvement (or intensity or responsibility, etc.) to counter balance the lack of months you've been at it.
2.What GMAT score is required for getting into top notch MBA colleges? Normally i would say it depends, but given your applicant pool, you are going to be competing against some really outstanding scores, so I would certainly put some extra effort into trying to get your GMAT over 700.
3.What would be the best time for me to take up the examination in-order to get admitted ASAP? Short answer is you should take the GMAT when you are ready. It would be foolhardy to rush in unprepared just to try and meet a deadline. Many schools have rolling deadlines, or at least multilple application windows (rounds), so it shouldn't be a problem to wait until you are prepared. In a way, your question confuses me, since there is not an advantage to getting in "early" because you would matriculate at the same time as everyone else in the class no matter when you were accepted within any given application cycle. Right now, there are still a few opportunities to apply in round 3 for fall 2011 admission, but it is unlikely that you would be able to have everything put together that quickly. Also, it is generally accepted that the later the round, the more difficult it is to get in, so you would definitely be at an advantage to target fall 2012 matriculation and submitting your application in the earlier rounds which will be this fall. I might also add that there are some schools which have an early application round where they give preferential treatment to your application if you agree to accept their offer of admission if it's granted. this might be something to think about for someone like you who faces a few critical challenges.
4.I have achieved various technical(ORACLE/IBM) and process certifications and have achieved high percentages(96-98%) in those certifications.These all are done during my job tenure.Will these count during my admission process? Certainly you should include any certifications in your application. Truthfully, the commitees won't value the technical certifications nearly as much as having demonstrated smarts and dedication to achieve them. In other words, it matters less what it is you achieved and maybe more how hard it was to get. Schools liike Sloan, Stanford, and GA Tech might be the exception and perhaps would be more attracted to some of these type certifications than other b-schools.
5.For my present work experience and profile what all top colleges I can aim for? The top ten are fairly comparably competitive, so you should choose a school which aligns with your interests and seems to be a cultural fit. I would try to visit as many as you can--it is hard to get a feel for fit from a brochure or website, plus it will demonstrate to the committee that you are serious about their school.
6.What would be best time I can apply for colleges? I believe I answered this already in the question #3 above.
7.Recommendation letters I can get from my professors but not from my superiors from my office.I can only get bonafide letters from my work organization and also recommendation letters from my colleagues in my office.Will it impact my admission? If what are the other possibilities/alternative I can cope up for this loss? Why can't you get recommendations from work? It can sometimes be suspect if you don't have anyone who can vouch for your professional performance. Turning in academic-only recommendations would be a risk. I would try to find a trusted superior who has worked closely with you and would be in your corner. Most employers support the advancement of their employees and in general they can't hold it against you if you want to better your education, so you might be surprised how accomodating they can be. If they would not be in support of you going back to school now, then realize that the adcom might agree with them. The average number of years work experience is over 5 now at most top schools, so you will need to really work hard to demonstrate that what you have to offer from your life experience both professionally and personally will be of value to a class full of more seasoned professionals.
I know I am biased as a consultant, but you definitely seem to be a good candiate for consulting help. Having someone guide you on how to cast your story to an adcom can be very beneficial, especially if you have some challenges to overcome. As many as 50% of applicants to top schools are using consultants these days, so you should consider it too whether or not you use VEritas. We would love to help you, but in fairness there are plenty of good consultants out there. I happen to really believe that the Veritas model is the best one, but consider getting some advice from somewhere. Good luck.
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Bryant Michaels
Admissions Consultant