The TiVo folks have this great feature on their website that enables TiVo owners to program their TiVos over the Internet. You have to have a Series 2 or Series 3 TiVo and you need to sign up for the service…but when you're away from home, all you need is Internet access and you can tell your machine at home to record a specific show. This has occasionally come in quite handy for me.
Now, they've taken it a step further. It's still being beta-tested but m.tivo.com is a similar site configured for mobile phone access. Again, you need to be signed up for it…but once you are, you should be able to use your iPhone or Blackberry (or similar instrument) to program your home TiVo. I'll try it out tomorrow and report back to you on how it works.