Right after launching Office 365, Microsoft released Service Pack 1 for Microsoft Office 2010 (KB2460049) which includes Office 365 support besides a big list of fixes. For those interested, Office 2010 SP1 can be downloaded here (x86) and here (x64). For a full list of changes, check out Microsoft Office 2010 Service Pack 1 Changes Excel sheet.
More interesting for Exchange folks is that there’s also an SP1 for the Microsoft Office Filter Pack 2010, which of course you install during Exchange setup as one of the prerequisites. As you probably know, the Filter Pack is used to index Office documents stored in Exchange databases to speed up queries.