The utility to read a shapefile, and produce a text description, is OGR. http://www.remotesensing.org/gdal/ogr/
Included in the distribution is a tool called ogrinfo. Executing the following command will dump the contents of a shapefile
ogrinfo -a example.shp
There's a Perl script (a very unpolished script) which processed STDIN into GeoRSS.
