Has anyone seen any native software for both Mac OS X and Windows that allows for seamless GTD transfers? I use Windows at work, and a Mac at home. I would love software that would synchronize items between the two platforms via email, file transfer, etc.

Am looking at software like Midnight Inbox on the Mac side.

A web site would be OK, but I am thinking about client integration with Apple Mail, Outlook, etc.

--Loyd