One of the feathers in my hat from working at m-Qube was working with carriers and establishing connections to pretty much every carrier in Canada and the U.S. It was more than tool jockeying, I actually wrote the software that these carriers interfaced with. I also had to deal with the various technical personalities, reasonable or unreasonable. Anyway, all the software I wrote (I'm guessing) isstill operating at Verisign, putting the food on people's tables. (And probably still spamming (other) people's phones, but let's not go there.)
For testing purposes, I'll soon be the proud user of a phone from Mexico, so I can complete testing of standard and premium messaging, and perhaps enable WAP push as well. ¡Hola! Don't be surprised if you get a call from out of the country.
Last weekend I spend about 20-30 hours total on this, working late Friday and Saturday. And then in a five minute space of time from when I had the number, I had it up and sending messages. This is a small miracle considering how fussy software can be. And the people I'm working with gave me a virtual "hi 5" which is nice to see in the IM window.