Great, lets start from the beginning.

[farahm2]

Okay people so now my iphone is pretty much brand new, i just formatted it last night and i want to jailbreak it again. Im pretty sure that its up to date with the latest firmware, but ill get back to you guys on that after school. So where do i start? What things do i need to know beforehand, and what things should i be cautious of?

I gotta run for the bus now, but ill get back on this topic at 2:30!

Bye!

[NeoNightmareX]

If you have a 2G (metal-back) iPhone and are using a Windows OS, it could not be easier. If you just want to Jailbreak, it is even easy to do it for a 3G.

You just need to use Quickpwn (link in tutorial) and follow the tutorials here. If you want to unlock the 2G, just update in iTunes normally and have the sim card that you want to use inside the phone during the process.

iClarified - iPhone - How to Unlock/Jailbreak Your 2.x.x 2G iPhone Using QuickPwn (Windows)
iClarified - iPhone - How to Jailbreak Your 2.x.x 3G iPhone Using QuickPwn (Windows)

[farahm2]

Thanks for the links, NeoNightmareX. I will definitely check them out soon. But before that, i just wanna say a couple of things. First of all, i want to jailbreak my 3g iphone. but i DO NOT have a sim car in it, (meaning im only using it as an ipod for now, and i cant make calls)so would that affect anything for the jailbreak?
Oh yeah, i also was wondering what happens if there is an update for the iphone and it is jailbroken? Do you have to un-jailbreak it and then re-jailbreak it?

[NeoNightmareX]

I don't think that having no sim card would prevent you from jailbreaking it. Also, if there is an update and you choose to update the firmware, it will be stock, so you would have to re-jailbreak it.

[farahm2]

Wait, so when there is an update, only the jailbroken data will go away, right? All my music and normal apps will remain, right? So anyway, if there is an update and i choose to go through with the update, do i have to wait until there is a jailbreak that is available for the new firmware version? Or do i just update and then jailbreak right away? And also, is there a way of backing up all my jailbroken apps and data, so that when the new update's jailbreak is available, i can still have all the old stuff?

Also, when i jailbreak for the first time, does it format my iphone? Do i lose all my current apps and data? Or does will it remain there even after the jailbreak process?

And one last thing, how often is there a firmware update for the iphone?

[NeoNightmareX]

I would wait to update until there is a definitive jailbreaking method for the new firmware. Also, in Cydia there is an app call AptBackup which backs up your jailbroken apps. All you have to do is download it, hit "backup" and sync in iTunes so that the phone backs up in iTunes.

All your music/normal apps will stay there if you update the firmware.

If you jailbreak a phone with music etc. on it, all of it should still be there.