I was wondering, if I jailbreak my iPhone iOS 4.3.1 do I have to redownload all my apps from the app store?

Best Answer - Chosen by Asker

No you do not. I jailbroke mine and, although I do recommend backing your iPhone up on iTunes before jailbreaking, you do not need to redownload all of your apps. This is, at least, true for me - I used greenpois0n.

Hope this helps!