I wouldn't be totally against a 3rd party utility, though I didn't have much luck with GeoNames. I was thinking about creating my own service to transform the XML to GeoXML. Just upload the xslt to the service when I need to add a RSS layer.
I like the featureCollection option as well... I'll investigate that one.
Is there a way to bring in the RSS feed into ArcGIS Desktop and display that as a map service?
A typical feed might look similar to this:
<TrafficCams>
<Cam>
<name>Traffic Cam</name><description>A road in a town</description>
<lat>42.23</lat>
<long>-71.145</long>
<static1_direction>Southbound</static2_direction>
</Cam>
<Cam>
<name>Another Traffic Cam</name><description>Another road in another town</description>
<lat>41.20278779</lat>
<long>-71.03</long>
<static1_direction>Northbound</static1_direction>
</Cam>
...
</trafficCams>