You will have to 1st ask yourself why you want an MBA and why now. Once you are sure that you want an MBA degree next year, then prepare for the test and take it. The score will tell you how high can you aim (w.r.t. rankings). Then you could ask one of the consultants here which schools are ideal for you after stating:
1. your GMAT/GPA
2. your WE
3. your post-MBA interests
4. What kind of culture you want in the school
5. What extra-curricular activities are you involved in
Once you get the schools start reading their websites, articles about them, threads in GMAT Club, etc, etc and then decide the schools. Applying for Fall 2011 is kind of late but its perfect time to start for Fall 2012.
The reason "somebody" asked you to decide the schools before GMAT is because some schools don't require GMAT. But I think most of the top schools definitely require GMAT or GRE.