Apple just updated its store with some more info on when, exactly, we can expect the iPad 3G version to ship. Their exact wording is “by May 7th,” which may mean some iPad 3Gs will be delivered earlier, though.
As far as international availability goes, there’s nothing new in the Apple Store about that. Apple will announce international pricing and begin taking online pre-orders on May 10, 3 days after iPad 3G starts shipping in the US. Let’s hope Apple doesn’t sell them all out – again – by then.