Well, it looks like someone cracked the DRM on TiVoToGo, making it possible to decrypt the files on non-Windows platforms. It is C code which reportedly runs on Linux, Solaris, and Windows. (I'm sure someone will port it to Mac if it doesn't run there already.) This is the Wiki reporting the development, and this is the project page on SourceForge. It is open source, BSD license. Right now it looks like a geek-level solution - you run it from the command line. But I'm sure someone will wrap it in a nice package to make it usable for the average user.
TiVo will probably not be happy about this, but I'm not surprised. There have been ways to strip the DRM on Windows for a while, such as DirectShow Dump, using holes in the DirectShow mechanism, and it was clear people were working on a real 'crack' for the system to remove the Windows requirements. Pretty much any widely used DRM system will have people dedicated to cracking it. There is more motivation because TiVo has failed to support any platform other than Windows, leaving Linux/UNIX and MacOS users out in the cold since TTG was released. The lack of an official solution is always going to increase motivation for users to find their own answers.
EDIT: Here's a guide to using this on a Mac and another one for automatically using it with Galleon on a Mac.
EDIT: This landed on Digg - albeit indirectly. The person who posted it link to the PVRWire story which originated from this post.