I bought the Stone Canyon database containing all the worlds arches:
http://www.stonecanyonadventures.com/AANPAbout.htm
The program contains a fantastic wealth of information and is well worth the coin just for the database. Biggest problem with the program is it is extremely amateur. Its put together like some 16 y/o kids basement website. But all the arches contain a picture, location, lat/lon, history....
I'm still playing with the program but to really make it worth while you also need good mapping software, the know-how to use it and lots of spare time.
But if you heard of an obscure arch and want to know where it is this is your program.
Ice