Back in early 2005, I wrote an article for MSDN on implementing add-ins for Windows XP Media Center Edition 2005. As part of that article, I implemented an add-in that made it easy to jump around in a recorded TV show, video, or music file using the remote control, simply by entering a time code using the remote control's number buttons. In October of 2005, I updated the add-in for Update Rollup 2. Now that Windows Vista is out, I've updated it again for Windows Vista, and the new version is now available for download.
If you have User Account Control (UAC) enabled, follow the following steps to install the add-in (if you don't, just run the MSI):
1) Open a command prompt with "Run as administrator"
2) Run "msiexec /i pathtoaddin.msi", where pathtoaddin.msi is, you guessed it, the path to the add-in MSI.
Note that I removed a bit of functionality for this release, specifically the bookmarking functionality, as it interferes with the new mini-guide available in Vista.
As described in the article, using the add-in is pretty straightforward. While viewing or listening to media, press the right arrow on the remote or keyboard. Then enter the time you want to jump to (123 for 1 minute 23 seconds, 1053 for 10 minutes 53 seconds, etc.) and press enter. Pressing the left arrow instead of the right arrow makes the jumps relative instead of absolute.
I hope this is useful to you.