Now, this is something i wasent expecting to find: BT have an SDK! yes, BT, the phone company, have an SDK, and some of the features are really quite cool! You can send SMS messages, make phone calls, conf calls, and some other cool things. there are some limits: 10 SMS messages a day, 10 2min one to one calls, and 10 2 min conf calls with up to 4 people. very cool idea. hopefully when its not in beta it will be nice and cheap.
As an after though, this could be to phone and mobile traffic as Amazon AWS is becomming to Data and Computing. With S3 and EC2, Amazon put power and storage in the hands of the people. with this, BT look like they could be doing the same. I have some very interesting ideas about this: VOIP as a service for Developers! could you imaging having that? Or how about this: a button in your application that says call developer (or Tech support). users click this, enter their phone number, both phones then ring and each person can talk to each other! all programmatically. im liking this!
[update] in the post above, i mention VOIP. This is not currenty a service, but its something i would like to see done. I am not sure how its posible to do (Can voice be streamed over XML fast enough?) but it would be interesting!