For the most part, you can't use T-Mobile branded Android phones and keep the $10 plan, but there are a few exceptions out there that'll work (the HTC Panache and the Galaxy Nexus for example). Nothing is guaranteed to work forever though obviously.

There are a ton of other phones sporting other OSes that will work as well. HowardForums has a fairly comprehensive (though not a complete) list of phones that are compatible that you can check out. The column headers are pretty self explanatory except for the SIC (Strength of Internet Compatibility) one--you generally want a 3 (works with no modifications) or 2 (works with minimal modifications) for that column.

Additionally, if you aren't already aware, T-Mobile is starting to refarm their 1900 spectrum which should make unlocked AT&T branded phones work on T-Mobile web2go plans with full speed sometime within the next year or two.