Boxee folks helpfully host an APT repository (http://apt.boxee.tv/), but, as of this writing, only for Ubuntu 8.04 (Hardy) and 8.10 (Intrepid). But if you happen to run a later version such as 9.04 (Jaunty) or 9.10 (Karmic), you could still install from the Boxee repository through the magic of APT pinning. This method should work just as well with later versions of Ubuntu also.
If you’re looking for a program and need to find a package that provides it, AND your package manager is APT (e.g. you’re running Debian or one of its many derivatives, like Ubuntu), you, Sir, got a couple of options.
One way is to search package contents online at debian.org, or you could use apt-file.
For a server, I prefer to run the latest stable release of Debian, but once in a while I need a newer package than what’s available from the stable repository.
The solution is in the Apt How-To available from Debian. See section 3.8, title “How to keep a mixed system“.