Know there are a lot out there but thought I'd direct you to one more:
She's also had time to write this blog!I think that the Old MD Girl Blog is one of the best. Especially if your a non-traditional student who needs to get some perspective on the fact that you're not alone.
It's written by a student that kicked off her MD/PhD training at 29. Since then she's gotten married and had a kid. Just goes to show that it can be done.