How do you replace driver side mirror on 2003 chysler town and country?

It depends on whether it is just the mirror or the mirror housing that is cracked...

If it is just the mirror, you can buy a replacement mirror and put it in, after you remove the other pieces, but if it is the entire housing, you'll have to get a new mirror and mirror housing, basically, and I'm no car expert, so if it were me, I'd take it to the dealership for that.