If you would like to forgo compiling MythTV from source and just get down to business recording TV, there are packages available for a variety of distributions.
Until someone cleans up this page and puts in some more info, the only link you'll find is to Jarod's Fedora Guide, which has the instructions needed to download/install the packages for Fedora Core.
Fedora / Red Hat / CentOS
Mac OS X
Various versions of MythTV for Mac OS X are available, including both frontend and backend and up to version 0.20.2.