When i use redsnow does all the info I have on the phone stay or does it completely wipe the phone clean, So i need to restore on my itunes again.

The reason I ask cuz Im at work and I can use my work computer to do this since my home one kinda sucks.. but I dont want to update then not have any of my contacts and email etc for the night..

Thanks Guys

Hi.
I update (not restore) then use redsnow to jailbreak and activate. All of the information (inclide Mail, contact, calender data, my appps, my musics, picts...) remain on the iPhone. It sure does not clean the iPhone if you chose UPDATE in iTunes.
In case update does not work, you can RESTORE your iPhone to OS 3.0 BUT you need to back up your data to iTunes before restoring your device. After restore and jailbreak, you can use iTunes to restore your data back to your iPhone.
In any cases, be sure to back up!!!