Ops, I guess I should have said I was using a Jailbroken iphone

Is there anyway to update to 3.0 that doesn't require me to delete all my data?

I want to backup my iPhone 3G. I'm told I can't use itunes to backup my .ipsw because it won't work properly with a jailbroken iphone. Is there a way to create a restore of my iphone so that if something happens to it I can just restore it using my backup and have all my apps/songs/settings/themes/etc still intact? Also, I don't have a mac, know anyone with a mac or have a way of getting a mac.