A little late here, but I can personally confirm that iTunes 10.3.1 is jailbreak safe, at least in terms of the ability to install cracked apps with AppSync on iOS 4.3.2. I’ve seen other reports about its continued ability to go into DFU mode, etc., but have not personally tried that and have yet to see any confirmed reports on the matter from the leading jailbreak scene figures.
In a related note, please be advised that from initial reports, it may prove to be technically i possible to achieve a untethered jailbreak with iOS 5. This would be sad news for me, because a tethered jailbreak is simply not feasible; I need to be able to reboot my phone away from my computer. Let’s hope our jailbreak heros find another exploit!