Supposedly caught early, he's having surgery in December:
http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2006/10/29/DDLESH.DTLPhil's been my favorite member of the Dead for years, partly because I always thought he was the most musically adventurous of the band, and only partly because my friends would always locate on his side of the stage at GD shows, simply because it wasn't as crowded as Jerry's side.