PS3.Blog writes: "Hi everyone! A minor update to your PS3 system is now available via system software update v3.42 that includes additional security features."
Users who updated to PS3 Firmware 3.42 have now confirmed that Sony has indeed patched the PS3 exploit used for PS JailBreak.
ROCK ON !!!

Comments
So the likes of Sony and Microsoft can only do what they can.
I know a few people who have 360's that have custom firmware etc
I'm not sure if Sony can do the same thing and ban an actual console from connecting online. I guess we'll have to wait and see how it all pans out. And @Coxlin - that is a crappy revelation, backwards compat should be standard at least to some effect