Jan Tielens posted the other day about their newly released "U2U RSS Feeds for SharePoint 2003," which is another tool for creating RSS feeds from SharePoint lists, but with some improvements:

Aggregation of items stored in multiple lists on multiple sites
You can create an RSS feed that contains information coming from more than one lists (or document libraries), that are potentially on different sites.
Customizable layout of RSS itemsFor each list that you aggregate in an RSS Feed you can specify how the items in the RSS feed should look like. You can do that by using some sort of formulas, referring to fields coming from the SharePoint lists.
Non-intrusive installation
The installation of the RSS Feeds tool doesn’t change a thing about your SharePoint installation, the IT-Pro guys will be happy! The tool is completely separated from the SharePoint sites and doesn’t require you to add metadata or web parts to SharePoint.
SharePoint AuthorizationAre you afraid of exposing sensitive data? Well you don’t have to, our tool uses the SharePoint security model, so if a user doesn’t have access to the SharePoint list he or she can’t retrieve information from the RSS feed. Anonymous access to RSS feeds is also supported (if your SharePoint site is available for anonymous users of course).
GUI Administration
The administration of the tool (creating feeds, item layouts, …) is completely done by using a nice graphical user interface.

Software: http://www.u2u.net/software.aspx

Quick video tutorial: http://www.u2u.be/downloads/tools/U2URSSFeeds.wmv