I'm in the same boat! My DH does the morning drop off at school and I do the afternoon pick-up. Both girls attend an after-school program but pick up is 4:30 and I'm 30 minutes away - so school ends at 3:10 and I have about 45 minutes to finish up the days work and head out to get the girls.
For me, the answer is to come in early. I used to be better about this but now the girls are requesting "mom" in the morning for hair-do's, etc. more and more. We have to be at work by 8:00am and I find that if I get there by about 7 I can get a lot done....it's quiet, not many co-workers stopping by to chat and best of all my energy level is much better than at the end of the day when I'm usually drained.
Good luck finding a way to make things work for everyone!
Judy