The Highpointers Club doesn’t have a definitive online guide. There are plenty of books available at the Highpointers Merc.
The best sources now for current information are two interactive sites: summitpost.org and wikipedia.org. Of these two summitpost is the definitive choice among climbers. However wikipedia lets you edit the description directly. This produces some amazing information on the mountains. The wikipedia articles are relatively young so your help is definitely wanted there.