A word of advice: if you plan to leave the country for two months, you might not want to do it during February sweeps, because it will really tax your TiVo. Before I left, I carefully planned what to record on my TiVo, what to record on my DVR, and what I could get on iTunes or Amazon's Unbox. Unfortunately, my TiVo didn't cooperate and failed to record anything after January 22. (My best guess is that the cleaning people moved the wireless adapter, and so TiVo couldn't connect to the internet after January 11, and thus ran out of program information. Bummer.)
But, luckily, Amazon Unbox came to the rescue for almost everything. Unbox is basically like iTunes and lets you download episodes of shows for $1.99. It used to be that you had to watch them on your computer, but while I was away they announced a deal with TiVo, so that you can now download them straight to your TiVo (assuming that your TiVo is connected to the internet).
It's pretty awesome. There are not quite as many shows available as there on iTunes, but you can watch them right on your TV without having to first download them to your computer, then to your iPod, and then hook up your iPod to the TV, as you would with iTunes. Also, you can save them indefinitely in your Amazon media library, without having to take up space on your computer or iPod.
You can also "rent" movies for $3.99, which means you have 30 days to watch it, and 24 hours to finish it once you start watching it.