Back when I was in the seo business a year or 2 ago, I always wanted to set up a free sms site because it would be easy maintainance.. however ive never found a working script for it? I know that these sort of scripts no longer work for uk mobiles, but surely there are some that work abroad? help!?!?
To send texts to mobiles you would need to pay for an sms gateway. Found a website that sells UK ones, but I'm sure there is a lot cheaper around. http://www.txtlocal.co.uk/prices/ Figure you'd be able to find an existing script to work with their API, but just having a script wont allow you to send texts.
No you can't just send texts using php. It merely acts as a front end. Just checked out the website eXe recommended and they offer free texts to the US/Canada for developers, but if you want to send UK texts they are charged at 2c each. http://evolution.voxeo.com/worldwide/rates/us_outbound.jsp
The free sms sending services that you're wanting to emulate are likely to be advertiser funded. So, it's free for end-users, but there's an actually cost associated with maintaining the service on the backend.
so to summarize, its not possible for me to offer free sms to people without me having to pay for credits through some means or other?