Assuming you're talking about the old Series 1 TiVos, yes, there's a way, but it involves a lot of mods. Basically, you'll have to get an Ethernet card installed in the unit, then upload some FTP software to get the files off the machine. Once downloaded, you'll have to run them through a converter, then burn them.
Series 2 TiVos have TiVo To Go, which is a lot easier, but still some work.
Try here for an idea of what you need to do.
Link