Laundry in by 8:30 is returned to your room by 6:30. You just call them up in the morning and tell them you have laundry - they come get it. If you are about to leave, just leave it inside the door and they'll open the door and grab it.

You can call the night before, if you want. I always call in the a.m. because I figure there is less chance of them losing it or screwing up.
They return it to the room and will hang it in the closet if you aren't there. I've had them screw up and forget to return it on time, but a call to housekeeping gets it sent right up, even at midnight.
Disney absolves itself of responsibility for ruining your clothes, so caveat emptor. They mangled one of my brahooks and shrank a few of my shirts. I had a white top come back slightly less white once, too. I only send out stuff that won't be too small if it shrinks now. But, generally, they do an OK job.
Laundry (not dry cleaning) costs:
Socks, Underwear, undershirt, bra, handkerchief - $2.00
T-shirt, slip - $4.50
Tennis shorts, knit shirts - $5.00
blouse - $5.50
Jammies/nightgowns - $6.00
pants - $6.50
Sweatsuit - $7.50
If you send them silk, linens or pleats, they add 50%. If it is lined they add $1.00. For an extra 10%, you can have the shirts folded and stuck in a box.
There is also a mysterious "environmental fee." Last time, for me, it was $1.47. It differs from time to time, though.