It's called the Mary Charles Yarn Company, and it's located on Sunset (which is a block north of Rice Boulevard), about 4 blocks east of Shepherd. It's a little tricky to locate, as it shares a building with another store, and is *upstairs*, but the address (1710 Sunset) is on the mailbox on the front of the building, so just trust that you're in the right place and go on in. :)
The phone number isn't on the website, for some reason; it's 713-529-2283.
It's a nice little place, with a decent selection; some novelty yarn, but also a good solid selection of wools and cottons. She's still kind of getting organized, but it looks like it's going to be a comfortable layout, with places to sit and knit awhile, and it's very light and airy. I'd definitely check it out, if you're on that side of town!