Screensharing is broken for me in Lion. In Snow Leopard I connected using mobileme for verification. However since upgrading my machines to Lion and my mobileme ID to iCloud, I'm unable to screenshare using my iCloud ID.
The Mac Mini I'm trying to connect to shows up in my finder. If I select the Mini, hit the "Screen Share" button and "Connect using an Apple ID" which has my icloud (.me) e-mail selected, I try to connect and I get an "Authentication failed" message.
Back to My Mac is turned on in iCloud preferences on both computers. Under Accounts, my iCloud e-mail is associated with the Admin account.
Not sure if this is just a bug that needs to be fixed of if there's something I'm missing here..