SqueezCenter supports plug-ins built by third parties. You can install them using the plug-in installer. Go into SqueezeCenter and click settings. The select Advanced -> Extension Downloader. From there you can select a range of third party plug-ins. If you don’t find the one you are looking for you can add other repositories. Here is a list of other repos.
http://wiki.slimdevices.com/index.php/SqueezeCenter_Repositories
If you need to add a plug-in that is not in any repo you can install it from command line. Put the plug-in into
/var/lib/squeezecenter/Plugins
and unzip it. Then go into the plug-ing manager in SqueezeCenter and configure it.