I purchased a Boxee Remote, which is an RF remote so I don't need to mess with lirc or anything like that.
How do I get it working in Ubuntu for use as a media center remote?
The remote itself is recognized out of the box with no set up, however if you are running 10.10 the X server needs to be patched or it crashes (see below for instructions). Unfortunately there is no support at all for versions earlier than 10.10, which includes older versions of XBMC Live.
If you use 11.04 and later all you need to do is remap the keys:
Remapping the keys
This post on the XBMC forum has information on how to remap the buttons to be more effective.
Then restart XBMC. I also found it useful to turn off mouse support in XBMC's settings.
Support for 10.10:
Here's the short version:
Then either restart X or reboot.