I have a friend who bought a USB turntable from ION (
http://ion-audio.com/) and says it's easy to use. THere are three models, which you can learn more about on the web site. Go to the "Products" pull-down menu.
One caveat: he doesn't use a Mac, and I saw some reviews, among the large number of very positive ones, that indicated tha included software doesn't work with a Mac. Several say that you can use SoundSoap, or ROxio's sound editing software with the ION turntable.... I don't know for sure.
I'm thinking about buying one, and would like to hear anyone's comments...