Outlook 2010 is something special. Even though Windows has been available as 64 bit version, Office so far hasn’t. So far. Now, with Office 2010 that has changed. Whether it’s much of an advantage for the user, I won’t try to judge.
For the developers however it’s a challenge since it requires major changes. Easy2Sync for Outlook has now mastered these challenges and is available both for Outlook 2010 32-bit and 64-bit. It does that completely automatic, so you don’t have to worry about downloading the right version.
More info about it on the Outlook sync page.