I installed XBMC with aTV, along with some other third party programs listed in the FireCore menu, and now when I use the Web Browser to look at some webpages I receive a message saying AppleTV is low on memory.
Is the low memory associated with my installing this? And if that is, how can I uninstall the extra programs I realize I will rarely use?
No, unistalling XBMC will not help with a low memory warning.as it is refering to RAM not to storage space.
The ATV2 has 8GB of Flash storage that isn used to store programs and media and this is where XBMC is stored. You are unlikely to use up all of this storage space.
The ATV2 also has RAM (I think 256MB) that is used to run all programs that are active. It is this RAM that can run out, and the only fix is for programs to be re-written to be more conservative in their memory usage so that they can fit in with this constraint.