Speed channel carries the Porsche Super Cup races, which are held at the Grand Prix events as "warmups" to the big F1 show. See http://www.speedtv.com/programs/299/
There are also lots of Porsches running in the lower classes of the Le Mans Endurance series and ALMS,as well as Grand Am and Speed GT series.
TT
Tom Tweed -- #908 SDR Tech Inspection Chair 2005-06 SDR Forum Admin 2010-present Windblown Witness Assistant Editor 2012-present Driving Porsches since 1964
Also, if you happen to have Time Warner digital cable, check out the new Speed Channel On-Demand. Right now theres only two items, but one of them is racing which includes some Porsche 356s, as I recall.