When you have a wifi connection then you have internet, you don't need it on your phone plan. Over wifi you can use Cydia, Safari etc
You should only use 2.2.1 if it is a custom firmware file that has been made with Pwnage tool to retain the old baseband, otherwise you will lock your phone. You are safe staying with 2.2.0.
oh ok....i don't have mac i have a pc....and for my understanding pwnage in only for mac user.....that's why i'm stuck