Universal Sports channel, available on some local cable systems, (and through the air on a digital 'side' channel from NBC's local
affiliates, probably including digital over the air channel 30.3) . will begin airing matches from the recent World Championships at various times & days beginning in mid-May 2009.
Repeat broadcasts are expected throughout the summer and early fall and streaming video of even more matches are available archived at ITTF.com
The digital signal may be available even through a cheap rabbit ears antenna - if you are close enough to the station towers and can't get it through your cable provider.
You would need a digital TV set rescanned for broadcast channels after you temporarily attach an antenna in place of the cable, or the add-on onverters available at Walmart and other stores for around $50, attached to a recorder or old-style non-digital TV set.
If you have a high-speed internet connection, iphone etc, matches from past events are often available at Youtube, and current and recent tournament matches are also available to stream or download at sites like ITTF.org.