new iphone release

I have an unlocked iphone 4 running OS4.1, which I jail broke with limerain. I would like to upgrade to 4.2 and here are a few questions:1. I’ve backed up everything already. Shall I upgrade to 4.2.1 via iTunes or download the upgrade file separately from other websites? 2. do I need to restore my phone before upgrading? Or do I just upgrade with whatever is on the phone right now and perform the jailbreak after?3. Would it be a problem that I jailbroke with limerain and now I Am thinking of jailbreaking with greenpoison? will things be messed up?thanks
yes, just update via itunes and jailbreak with greenpoison.
here is what you do. get greenpoison as that is what i use. Sync everything to computer. download the version you want to jailbreak. then put the new update on your iphone 4. After that, open greenpoison. follow instructions. simple as that. and it doesnt take super long.