The Chronic Dev Team has announced that they've found 5 userland exploits in iOS 5 making it very likely that an untethered jailbreak will be available for the upcoming firmware.
The iPhone Dev-Team has released RedSn0w 0.9.8b7 which brings support for the new iOS 5.0b6 iPad 1 build and adds explicit support for a tethered 4.3.5 jailbreak.
iDongle is a prototype piece of hardware able to boot your jailbreaked device (a.k.a "tethered boot"), and optionally jailbreak and hacktivate it if not already done.