Apple has released a new Mac OS 10.7.2 seed and a new beta of iCloud for Mac and both are required to complete the transition from MobileMe to iCloud.
10.7.2 release notes:
This pre-release version of OS X Lion 10.7.2 is being provided solely for testing iCloud and updates the public release of OS X Lion and any earlier seed of OS X Lion 10.7.2. If you installed a previous seed of OS X Lion 10.7.2, please run the included reversioner package followed by the OS X Lion 10.7.2 update without restarting your system. You should restart your system after installing the OS X Lion 10.7.2 Update. (Mac Developer Program membership is required).
iCloud for Mac beta 6:
iCloud Add-on installer for OS X Lion. (Mac Developer Program membership is required).
Via | 9to5macTags: Apple mobileme