This has I believe made To Dos and Notes even more confusing. I think I have it figured out, but noobs are gonna be lost.
After switch to beta here is what I see.
As others mentioned, in iCal it now says
myname@me.com above the calendar at top left.
In Mail for Notes I have On My Mac and MobileMe. In Mail for To Do I have On My Mac, MobileMe and a new since the beta entry called
myname@me.com. All my To Dos from the MobileMe section were moved to the new
myname@me.com section.
The To Dos in
myname@me.com DO NOT get synced using MobileMe. They apparently get synced to CalDav along with the calendar events info. I can tell because on a second machine To Do changes do not appear after a MobileMe sync, they will only appear after I open iCal and it syncs with the CalDav server.