You can find the the Mac Office 2011 VBA reference docs at http://mac2.microsoft.com/vb/1033/default.aspx?src=office.
In almost all cases, the PC version of Office 2010 VBA references are concurrent with the Mac Office 2011 versions, but you can locate the Object Model Changes from Microsoft - Product - 2010 on each product under the Visual Basic Help page and you'll see what may have been added, removed or changed. For example, here is the Object Model Changes from Microsoft Word 2010.
