Yeah, if your jailbroken hold off updating to 3.1 if your planning to jailbreak again in the future!
iTunes 9 is swish. Home Sharing is superb - I can't believe Apple have gone with it. They'll surely lose many sales because of it.
For those of you who don't know, you can share all your music / Apps, basically anything in your iTunes library, with up to 5 other people on a LAN.
So essentially, one person could buy the TomTom app, and then give it to 4 other people, meaning you could all split the cost.
I've tested it with the Beejive app (shared it with my brother) and it works. It just seems too good to be true, but.. it is true!