Justin has a nice theme developer oriented review of the nav menus.
Ron talks about upgrading from MU to 3.0.
The first cut of automatic upgrade is in trunk. It is hairy, ill-tempered and eats kittens. You can use it to automatically upgrade to each nightly build if you are brave. Don’t use it on blogs you want to keep.
Committed automatic plugin upgrade. We’ll see if we can stabilize it in time for 2.5. If not, we’ll move it to 2.6.
Trying to get automatic plugin upgrades in good enough shape to commit before feature freeze kicks in.