Thunderst0rm is “supposed” to be an untethered jailbreak for 3.1.3. It was released today and is available for download. Thunderst0rm is fake. Do not download or run it. We aren’t sure what all it does, but it does not jailbreak your device. Furthermore, it may install some spyware or something. It should be avoided. Rumors say it deletes several files from iTunes meaning you would possibly have to reinstall iTunes after running it.
Another one called TurboSn0w2 is also fake.
There are currently 2 known working exploits on 3.1.3/3.2 (ipad). One will be released from Comex called “Spirit” and the other by Geohot which will probably be one of his “Ra1n” apps. The two folks above are working together and will make sure that both are not released for the same device firmware. That means the next two major apple releases should be able to be jailbroken without looking for additional exploits.
If you don’t see news about it here, at the iphone-dev team blog, or at Geohot’s “on the iphone” blog, assume that it is not real and do not run it until you see confirmation at one of the above sites.