Can be found here: http://www.tv-now.com/stars/rculp.html
(awesome site, I'm so glad I found this on the GAH board!)
I also just learned that on Yahoo's TV area, you can do an advanced search by cast member, up to 14 days ahead! I discovered "I Spy" is being shown on ALN (AmericanLife Network)!
I've been using the Yahoo feature, because once you do the search and look up the listing, you have the option of adding it to your Yahoo calendar. It's making it very easy to track Culp's TV shows, guest appearances and movies! October 12 is going to be fun; he's in "I Spy," "Everybody Loves Raymond" and "Diagnosis Murder." It'll be a Robert Culp day!