I routinely add sites to the Links area at the MPworks group site.  
Most of them do not contribute much info.  Some retailers actually 
have better info on their sites.

The Peter Eaton Clarinet Mouthpieces link I just added does have a 
few screens of interesting reading.  It includes his views on 
choosing a mouthpiece, table flatness and facing measurement.  He 
measures (and marks his pieces) from the very tip to the very 
beginning of the curve where it meets the table.  Take a look.

If anyone else stumbles on or has a mouthpiece site I have not 
listed, feel free to add it.  There are a number of clarinet sites 
missing from the list.