I loove hair wraps, and I always get them at Disney (they're like my good luck charms).
The best place to get a hair wrap is at a deluxe resort. For the past...three years or so, I've gotten mine at the Polynesian from the same CM...Katherine is her name maybe?? I don't know, in any case, she gives really good, really tight hair wraps.
When you get your hair wraps elsewhere, it can be hit or miss. Katherine told me that usually they put the new (and inexperienced) hair wrappers in the parks. There is a hair wrap place at the MK (by Pirates), at the AK (on Discovery Island), and at Downtown Disney (in the Marketplace). I believe there have them in the other parks as well, but I'm not quite sure where. (Is it on New York St. in MGM...and then...Future World in Epcot maybe??)
ANYway, the hair warps I have gotten at the Poly have stayed in for three months and they're still perfectly nice. You just have to make sure you don't catch it when you comb your hair. (otherwise the top piece of hair it's attatched to gets all ratty). Hair wraps often fall out quicker with longer hair (they break at the root b/c of the weight of the hair and the string and everything), but mainly, if you take care of it, it stays in for weeks. And then, when it falls out, you can still pin it back in later! (usually it falls out in one piece, or you can cut the hair at the root)
On the other hand, I once got a hair wrap at the AKL (they don't do them there any more) and it fell out the NEXT day!

I went to another hair wrap place and they replaced it for free, and then it stayed in for much longer.
They have hair wrap stands mostly at Deluxe and Moderate resorts...I've never heard of one at Pop, but we haven't been there in awhile. Maybe call and ask?
If you can, though, I'd definitley advise getting one at the Poly or another deluxe resort. The stands are usually open from 11 or 12 to 5. If you go right at 11 or noon, you can usually get it right away. Otherwise, you might have to wait.
Just general info: You can choose up to four colors, it's $2 an inch. There are tiny beads that are 50 cents each, then more fancy ones that range from $2-4 a piece. THEN you have to get gold or silver spacers to go in between the beads that cost 25 cents a piece(for the little ones that go in between all the beads) and 50 cents a piece(for the big ones that go on the very end - you only ever get two). Oftentimes, though, the CM's won't charge you for the spacers. I don't know if this is bad math or tradition, but it's pretty nice!
It usually takes 10-15 minutes to get a wrap, but there are premade ones with clips that you can buy for $15 a piece or $25 for two (can you tell I've listened to these sale spheles many times?)
Sorry that was so long, I just love hair wraps.
I have to admit, though, that hair wraps don't amount to much of a "hair-do" because it's just the one strand of colored hair. So if your DD wants something more fancy, you might want to thing of getting the hair wrap clips (so you can get more than one to use) or they sell fun hair extensions, clips, crowns, etc. that they use at BBB, but you can just by the extension or clip. They sell those at World of Disney and around the parks (I think...)
As far as I know, they don't do hair braids at Disney, but I could be wrong.