I've been trying to ramp up my knowledge of mobile and SMS. Every time I find a small tidbit of information it always leads me to 10 other things I want to read up on.
What I found this morning:
List of providers of short codes, short codes for SMS reverse billing and premium SMS, SMS messaging:
Comparison Table of SMS Gateway Providers (SMS Service Providers, SMS Resellers, SMS Brokers).
This site also has a good Short Message Service / SMS Tutorial as well as tutorials on WAP CSS / WCSS, WML, and XHTML MP.
Another page that I'm interested in: SMS Tutorial: How to Receive SMS Messages Using a Computer / PC