Jailbreak Question!

[tlu]

Hello, well im new to this whole jail breaking thing. I just decided to look into this jail breaking thing today. So i noticed there are alot of different programs/ways to jail break the iPhone. I was wondering if theres any difference between the programs.

Im running on a Windows Vista Home 64Bit Laptop.
I had a 3G iPhone Version 2.2 w/ AT&T when i jailbroke mine.
I used QuickPwn 2.2 and this iClarified - iPhone - How to Jailbreak Your 2.x.x 3G iPhone Using QuickPwn (Windows) guide to jail break it.
So i was wondering if theres any difference if i used Pwnage Tool, ZiPhone or any of the other programs, thanks. Oh yeah everything seems to be working fine so far. If i wanted to bring my iPhone back to apple if anything happened can i "Un-jailbreak" it? and will they know? cause i heard jailbreaking voids the warranty.

Also my gf wants to jailbreak her iPhone 2G w/ firmware version 2.2 already installed with AT&T. Shes also using windows vista. Im wondering if the method i use to jail break my 3G will work the same for her?
Thanks for the help.

[dejawoo]

ZiPhone is for 1.1.4 or lower fw
PwnageTool is for osx
So use quickpwn 2.2 2G for ur gf's iphone(windows)...

[tlu]

Which IPSW file do i use for the 2G?