I haven't written about this until now because, well, I couldn't get the darn thing to work. But where versions 1.5.5 and 2.0 had failed, version 2.1 of the TiVoDecode Manager finally allowed me to download a show from my TiVo. Sure, I could get them off of the TiVo before, but I either couldn't watch the file or had to work with it in Windows. This little unofficial, non-TiVo-blessed Apple Script wrapper does the download, decryption, and conversion to Mpeg-4 all on the fly. And, like I said, it finally worked for me over my Airport Express network, whereas the previous versions all died during the download process.
So for anyone with a Mac and a TiVo Series 2, give it a whirl. It sort of makes up for the official TiVo To Go Mac client becoming vaporware in 2006, yet again.