Apple has released an update to Snow Leopard, in OS X 10.6.5. It is available now, via Software Update.
With this update to Snow Leopard now in the wild, we should expect an iTunes update and an iOS update. iTunes 10.1 and iOS 4.2 have been in beta, for a while now. The GM of iOS 4.2 was seeded to developers not too long ago, so we should see that go public soon. Some speculate that we will see both of these by the end of the week.