This code example retrieves comment information from 23 via RSS and Google AJAX Feed API. It includes a quick and dirty function to get a bunch of meaningful object info about every comment in the RSS feed, and then there's a few lines to build the box with comment information.
Please note: The code in these example is particularly dreadful -- it's only quick and dirty demo after all. If you choose to use this code, at least clean up the regexp stripping HTML from the content.