obd II software for codes

hey guys,

i posted the other day about my 4l60e only working in reverse -- and how it might be in "limp home mode"

so before i do a R&R on my 4l60e i'd like to see if my computer is throwing codes -- and possibly erase those codes and see what happens. however, i'm not sure which software to use. i have a USB code reader thing i bought off ebay, and a laptop -- which software do you guys use? recommend?