Ohhh, this is sweet.

It even goes through the trouble of finding GPG keys for you. Seems to be working as of software-properties 0.75, which also brings along a command-line tool to accomplish the same thing: add-apt-repository.

Huge thanks to whoever worked on this. It is simply awesome, and will certainly make many developers' lives easier.

(And because threads are better than blog comments: http://ubuntuforums.org/showthread.php?t=1213538)