I noticed Tyler's version was down about a week ago so I finally got around to putting together an online version of the program on my own site:
http://carlinbamboo.com/guidecalc/
Not much is different except I added a third guide spacing option (Hybrid), added some technical info if anyone cares, and made it so each of the 3 spacing methods are dealt with independently - including parameter storage - in case you want to compare results. I haven't included the guide sizing option; I'm not sure I'll add that or not.