Thought it would be of help, to attach some resources i have had.
1. SMPPSim.rar this has a SMSC simulator, which simulates live Telco SMSC servers, hence allowing to test applications locally without having to connect to live Telco servers and pay them for the services.
download smscsim from here (attachment size 800kb+)
http://www.4shared.com/rar/ZVZ7qKJ0/SMPPSim.html2. smppclass.rar a php based class i have had for some time, which works just fine and can be modified to work in better ways to send across sms to these SMSC's of Telco using SMPP protocol.
Steps to follow to test the same.
1. smpp.php file has sample test script
2. smppclass.php is the class for smpp protocol (still lots need to be covered)
3. You can modify the smpp.php file to suit your local setup, by configuring the
$smpphost , $smppport, $systemid, $password and $system_type and $from.
These are preset to the simulators configuration for now for ease of use.
4. Simulator's configurations can be changed by going into directory conf->smppsim.props.props file can be opened in any text editor.
5. Run the "startsmppsim batch file"
6. Run the smpp.php file from any local server. and you should get the output on the web end.
and see the incoming messages on the SMSC simulator.
This is for SMPP based PHP conectivity to SMSC's
For web based, API's of Telco Operators, i shall share resources soon
Any feedback most welcome, I will be trying to incorporate the above setup into our installation of abantecart. will upload the progress soon