It is gone from Xfinity's channel lineup, which is something of a shock when you consider that the channel doesn't charge cable networks to air it. Petitioning KCTS definitely won't help because they don't own it. The good news that there is is that you can now view their content online via the link that andyross provided.
When I checked the web sites list of channels here in the Chicago area, they were all local college/university channels only available in a few towns each. It's hard to tell what, if any, fee they may charge the schools.