A whole host of SMS related services. The <a href="http://bmannconsulting.com/blog/bmann/sending-free-sms-website#comment-80465>commenter who mentioned had a great posting:
What a wild thread! So for my $.02 worth (euro, if only I knew the key-combo), I throw the ring at pswin.com which at less than a dime a pop ain't free, but so far that's been the best real deal, and *much* cheaper than actually calling the damn mobiles, in Europe anyway. I figure I can say what I want to say for less than a dime via sms, and if the other party, who forces me onto their expensive network in the first place, wants to contact me, they can pay whatever they feel its worth. Pfffft! That said, I've seen recent ads for even cheaper sms, but my ad retention is low. Still, I'm willing to pay for an actual web interface/ keyboard combo. I'm not willing to pay to call those damn pricey little phones. hrrmmmph. oh, one nice thing about pswin.com, I can enter whatever i want (subject to non-abuse terms, natch), into the 'sender's address/number field. I can actually write my name, as opposed to my cell number, which I might prefer not to.