Jailbreak and activation works exactly the same as in previous betas. You have to use Beta 5 firmware file in latest redsn0w in order to jailbreak and boot tethered. You will need updated bundle in order to skip headache.
You will need latest beta version of iTunes 10.5.
Latest redsn0w 0.9.8b5: Windows | Mac
You can find both latest iTunes 10.5 and iOS 5.0 Beta 5 here.
Updated bundle links: Ziddu | Mediafire