Comex recently tweeted that JailbreakMe 3.0 will only support 4.3.3 due to the recent leaks. If you don't know what JailbreakMe is it is a Userland Exploit Jailbreak for Apple Devices. It works by exploiting a PDF exploit opened up in safari allowing unsigned codes to install Cydia APT installer.
Quote (Comex):
4.3.1 and 4.3.2 will not be supported since I'm in a hurry; upgrade to 4.3.3
(if you're patient, I'll add support for those versions, and 4.2.1, and maybe armv6, in the future)