First off what version of the OS are you as thats sorta important? Also you will need redsn0w and the OS and then the redsn0w GUI will walk you through the process.
my problem is my ipod touch 3g dont connect to my wireless at home so i cant downlaod the cydia or what ever it is so i can instal free apps :/ such a bastard tbh, is there any easy way around it?