From DVRpedia

[edit] Overview

This feature allows you to schedule recordings on your TiVo using your cell phone. This is currently available though Verizon Wireless Get-It-Now for a monthly fee. This feature works only with Series 2 and Series 3 (TiVo HD) TiVos.

Note: If you have an advanced cell phone that has a real web browser (as opposed to a dumbed-down WEP browser that is on most low-end phones) and internet access from your carrier, you can browse to the tivo.com site, log-on to your account and schedule recordings that way.

[edit] Videos

Here is an overview of the service:

Here is a comedic video of this feature in action, from the Tonight Show with Jay Leno: