How to approach someone for a recommendation?

Yes, but I think the key here is that it seems you made such an impact and had the type of relationship with your employer that he definitely will distinctly remember you after 4 years. If you hadn't talked for a few years (which by itself might be ok if your employer still distinctly remembers you and your contributions) AND you were nervous about contacting him, then that probably indicates that this employer is likely not a good choice for a strong recommendation.

Good point. Hadn't really considered that aspect. I love the open discussion of this forum and getting to hear viewpoints from different perspectives. When you put it that way, it really does seem like MBA2BEE would be best served by getting both his recs from his current managers.

So in my situation, both rec's from current managers or 1 from current manager and 1 from old manager? Opinions anyone?

Well like most things application related, there isn't always one single answer. I think you need to know the program you're applying to. In my (limited) experience, some schools care more about how far in the past your interaction with recommenders has been than others. For example, I think it is really to your benefit to use the most recent (and of course impressive) recommenders/recommandations as possible at MIT. But other schools care less about the timeframe (within reason of course) and more about how well the recommender can speak to your strengths, experience, and impact (I got this impression from HBS).

But always remember that the most important aspect for a letter of recommendation is to pick recommenders that know you well, that can speak to your strengths, that can talk about specific experiences and accomplishments, and so on.

And I would suggest that if you do pick two recommenders from your current company, try to get two that have different types of interaction with you. Try to avoid getting two similar recommendations.

So like I said, there's not really a single best answer. You've got to take all of these points into consideration and figure out what works best for your specific application. That's my opinion, take it for what it's worth.

I am attaching the recommender form from Kellogg last year. All schools ask very similar questions. Honestly I dont think someone with 4 years experience would be best served by using someone they worked for, for one year, and the first year at that.

They want leadership experience, growth compared to others, all sorts of stuff that its useful to have as long a frame of reference and the most current view point on. So unless that person continued to mentor you after you left thats probably not the best person. Like I said schools care more about where you are now than where you were 3+ years ago. There are plenty of people who rise fast at first then come to a halt and show no progress while others continue to advance.

Also, another issue to consider is, is the recommender going to be easily approachable during the process? Working in the same company at least somewhat makes it easier - even with that sometimes busy recommenders are difficult to find when deadlines are looming. Take into account, you will probably need to "gently" remind them at least a couple of times.

I agree, vote early and vote often.

That is let them know WELL in advance and provide kind reminders throughout. if you give them like 2-3 months notice, they will feel that they are responsible if it is a few weeks before the deadline and they haven't done squat. If you give them only 3 weeks notice, they're going to be flat out be pissed off because then you are really putting some more pressure on them and potentially conflicting with meetings, vacations, personal events, etc. As I also said, kindly remind them along the way. I found that the backhand method to doing so was just providing an update of my own. "I just wanted to give you an update and let you know that I'm almost done with Ross" or "I've finished 2 out of the 5 schools." They'll feel obligated to provide an update of their own.