Iphone 3gs help with internet?

[Cameron]

So I have an iPhone 3gs ipsw 4.2.1 and it has no WiFi because water damage and i don't have an iPhone data plan just a blackberry data plan is there any way to get internet to the iPhone to install cydia so i can unlock the internet?? have tried tunneling and it wont work any other ways i can get it to work?? i have also tried jail-breaking but all jail breaks for windows make you have to install cydia over the internet after jail-breaking witch i cant do. and i can't switch to iPhone plan