u can use redsn0w 0.9.4 to jailbreak iPhone 3G and iPod touch 2nd gen (non-MC) and iPod touch 1G for firmware 3.1.3
i have a 3rd gen iTouch so im just gonna have to wait and see what happens
just use spirit its at spiritjb.com it works perfect just a click i use it each time i have to restore bu no 4.0 for that go to jailbreak.me in your safari browser on your idevice
you can always revert to 3.1.2 from this website: http://www.felixbruns.de/iPod/firmware/
alt/shift (mac/pc) click restore and load up the 3.1.2 ipsw and see if blackra1n works then