After installing the Microsoft Visual C++ 2008 Redistributable Package in the CrossOver Games Software Installer as per Chase Cavenaugh's tip, TA works perfectly. The game does however put up an error message about DirectX version incompatibilities (installing the latest version of DirectX in the Software Installer doesn't resolve this), but I've not run into any other problems so far.
Note that I've only tested out the first few missions of the Core and Arm campaigns and I've not tested out multiplayer.
On a Mid-2007 MacBook (2 Ghz C2D/2GB RAM/GMA950/10.5.8) the game gets a little sluggish at 1280 x 800 resolution; I currently play at 1024 x 768.
Edit: I used a Windows XP bottle for this install, as the VC++ 2008 package won't install in a Windows 98 bottle.