MythTV is an open source software digital video recorder (DVR) that is an alternative to Tivo or Windows Media Center. It allows you to pause and rewind live TV shows, skip commercials, schedule TV show recordings, and control a settop box using an infrared remote or firewire. In order to use MythTV, you will need a video capture card. Hardware requirements are described on the MythTV Wiki.
During the installation of PC-BSD the installer provided an option to install MythTV. If you wish to install MythTV afterwards, use the System Packages tab of System Manager. You'll find MythTV under Misc.
Note: if you have installed MythTV and don't have a MythTV desktop icon or entry in your window manager's Multimedia category, you can run mythtv-setup as the superuser to run the setup configuration and mythfrontend to access the MythTV frontend. Both of these programs open a graphical screen; however you will need to use your arrow keys instead of the mouse to access the GUI options.
Configuring MythTV for Multiple Systems
By default, only the computer running MythTV has access rights to the database that stores your configuration settings and recordings. If you wish to be able to access the MythTV database from other computers, you will need to change the database permissions.