PfhorSlayer let us know that work on version two of Aquaduct, the Mac OS X Xbox tunneller, is still ongoing:

Things are progressing very well, and we are gearing up for some internal testing and hopefully release in the not-too-far future.

Aquaduct can now tunnel games between Xbox users who have a Mac running Aquaduct and Windows users who have Xbox Connect; word is it will "probably" be out before Halo 2. Let's hope so.