I have T Mobile too for my wireless air card.  Speed sure isn't cane but it works in the courthouses ok.  29,95 for unlimited.  I have verizon for cell phone and would have loved to use them for the wireless card, but their unlimited is like $80 a month for the same  thing.
And with T mobile, any starbucks coffee place or airport and a few of the newer courthouses have what they call 'hot spots' where you tap into their network and it is like having a dsl connection.  Its great.