Elisa is an Opensource Media center made by the people who brought you fluendo. This is a walk through on how to install Elisa. Remember this is a walk through so I take no responsibility for what ever may occur.

Step 1: Go to System>Administration>Synaptic Package Manager.
Step 2: Go to Search, type in Elisa, and click search.
Step 3: When the search is done, right click on Elisa, which will bring up a context menu. When the context menu is open, left click on install.

Now you will want the plugins as well. So with that same search, go a bit lower in the package manager search and click on the elisa-plugins-bad, elisa-plugins-good, and elisa-plugins-ugly. Now along with the Elisa they will install.

Step 4: Click apply, when a dialog box pops up click apply a second time.
Step 5: Elisa and the plugins will now install.
Step 6: Now that Elisa and the plugins are installed go to Applications>Sound & Video>Elisa Media Center.

Update: The distro I use once again is Ubuntu Hardy Heron (8.04), The plugins that I have used come from synaptic package manager. Thirdly you can purchase the codecs, but since I am making less then minimum wage I tend to use the ones in synaptic.