Didier hacked together an implementation of URLCall on his new Python-enabled Nokia phone. Cool! He also used the word 'dial' to describe the concept which I think is better than 'call'. So a new name for the concept could 'DialWeb' except that it's being used for another telephony project.
[Update: Why not come up with an entirely new word by smashing Dial and URL together? Diurl! I might have heard the word before in my past lives…perhaps during the French Revolution? 😉 ]
Anyway, unless I misunderstood, his implementation runs entirely on the phone, thus requiring phone number to URL database to be on the phone. My ideal solution would use a server-side database accessed via a HTTP GET. URLCall client on the phone needs to know only one URL. With multiple HTTP redirection, you can even set up a hierarchical directory infrastructure on top of HTTP.
URLCall (level 1) looks at the first number and redirects to one of 10 Level 2 URLCall websites. Level 2 URLCall websites looks at the second number and redirects again. So on and so forth. Net result is a sort of poor man's directory infrastructure spanning the globe.
A more practical version would reserve the top rows of the phone pad (1,2,3) and '0' for special uses (i.e. anything start with 1 maps a personal URL like my bookmarks page) and then use the remainder plus the next three numbers to decide which Level 2 URLCall directory to route to. Numbers starting with '0' is a way to call local numbers. I think three HTTP redirects at the most is needed to address all the websites in the world with phone numbers.