An update (service pack) for AutoCAD 2011 for Mac has just been released after a very lengthy beta test cycle. After installing this update AutoCAD 2011 for Mac will support the Apple OS X Lion release as well a address several reported issues.
Download & Info: AutoCAD 2011 for Mac Update 3
Make sure to read the Readme document as there are important details such as update 3 not including the previous updates 1 & 2 so you must first install those updates if you have not already done so.