simply "wikipedia" email to sms gateway and you will see all results. This option is fine, but if you use it too much, you will considered spammer. So if you are trying to build a lasting business, be careful with it.
What I need is a comprehensive, cross-carrier list for sending email from cell phones. I've found this information for a few carriers, but it's not complete by any means. For instance, it looks like Cingular (U.S.) and Rogers (Canada) use the same method as T-Mobile (U.S.), just using a different number (500 for T-Mobile, 121 for Cingular, and 0000000000 for Rogers).
I may have to devote a few days to digging out this information by hand from the carrier web sites. If I do, I'll add it to the Wikipedia article.