the best "console" setup for streaming:
1st advice stay away form anything with only AV inputs, ive used a daazzle capture card but the quality was horrible.
buy the Hauppage HD PVR
http://www.hauppauge.com/site/products/data_hdpvr.html
it comes with handy software called Total media extreme
here is a basic tut on how easy it is to use the HD PVR and procaster to stream console games !!
http://www.youtube.com/watch?v=f3iz3HJ7Eos
good luck !!