Feel free to grab this web part (right-click, save-as) http://www.wssdemo.com/Downloads/SharePointSitesRSS.dwp
Add it to a web part page using the Import option (zero code deployment).

Thanks to http://sharepointrss.com/ for the DVWP generator+ a couple of tweaks to show all sites and cache the data for a day.

A sample page hosting the web part can be seen here http://www.wssdemo.com/Pages/RSSFeeds.aspx