I've been fortunate - when I got started in programming, I was able to work with a few brilliant people who really helped launch my career in software development. Since then, along the way I've been able to work with some other brilliant minds.

This was really more of a matter of luck vs. formal 'mentoring' program.

I think a formal program would be great, it's just a matter of planning it and making it work, carving out the time, etc.