I have just added a Google sitemap to the Content Management System. It was actually quite a bit easier than I expected. I haven't implement all aspects of the Google sitemap spec, just the bare bones however. The general creation of a Google sitemap consistes simply of an XML document with a list of all the URL's in the site.
For each page of the site. The Google sitemap spec also offers advanced functionality to describe how often pages are changed, and what their priority is in comparison to the rest of the pages within the site. I plan on adding this functionality later on so it is all editable through the admin.
So far, the Google sitemap has done very well for my site. After I added the site map to Google's database of sitemaps, I had all of my pages crawled within a day. Pretty good.