Here's some Tivo FAQ's that always seem to crop up in Tivo threads:
Can I use the Tivo without a subscription after the initial contract is up?
No, you must either pay for monthly ($12.95/mo) or lifetime service. Do yourself a favor and buy lifetime service for your Tivo right away
Do I need a phone line?
Yes and No. You can use a wireless or wired USB ethernet adapter with your tivo, bypassing the need for a phone line. To perform the initial guided setup, you MUST use a phone line or a WIRED ethernet adapter. If you're using a WIRED ethernet adapter, you should use dialing prefix ,#401 (that's comma, pound, four, zero, one). After guided setup, you can use a wireless adapter as long as it's supported. You might want to save yourself some headaches and just buy the Tivo branded one from their store online.
Can I watch one show while recording another?
This one is tricky. You can watch one recorded show while another is recording. You can't watch a different channel live while recording on another channel, unless you get fancy with your AV Hookups.
I have analog cable, it comes out of the wall into a high-quality splitter. One line goes to my TV, the other goes to my Tivo. The Tivo is hooked to my television via Svideo and RCA audio cables. I watch the Tivo on Input 1, so if it's recording, I just watch channels 2-100 on the TV. It works very well.
Does Tivo work with digital cable/satallite?
Yes, but you'll have to use the included IR blaster to change channels on your cable box. The HDTivo is supposed to have cablecard slots, but again, no one knows anything about the price.
Is Tivo worth it?
Oh yeah. If you watch one hour of TV every night of the week, you'll be able to watch all that TV in 5 hours as opposed to the 7 hours it'd take in real time. Once you get the Tivo trained with shows you like by rating them, it will automatically find shows you might like and record them. A good example is a couple months ago, I saw it had recorded Quantum Leap for me. It was on a 3am on SciFi, I had no idea it was being shown on TV still. It frequently finds shows I like and records them for me - there's always something to watch.