US SIM for us travellers

[dninja at gmail.com (Robin Wood)]

Hi
When I come to Shmoocon I'd like to be able to put a US SIM in my
phone so I can do data and voice for the week I'm there. Can anyone
recommend a cheap way to get pay as you go voice and data? I don't
need a phone and will probably only be checking mail and twitter so
not need too much data.

Robin