Hi

I am interested in building a sms service to mobile fones via web.

Are there any free tools for that?

Is there any proper documentation available on the www?

I googled, but got crappy results.

Thank You.

You can use lycos in the UK. I think it depends wher you are in the world though - not many compaines will elt you do it for free, especially international txts.

It depends on the operator. Nearly all have SMS gates, but not all allow to send SMSes easilly. For example: may have a number of messages from one IP (per day, for example) or need an extra password, or allow only a certain amount if you don't pay them extra.

You can build your own SMS gateway.
You just need to buy a GSM modem.
And You need a mobile line with a SIM card to be used with the modem. If you buy the modem, it will come with the user manuals, AT-commands lists, and programming guide. The modem will be connected to the PC though comm port and you can write the Gateway server, just normal serial comm communication, using any language. You have to use "AT-commands", provided by the modem which is the GSM standard to communicate with the GSM modem.
After finishing the gateway, you can write the web interface to it.

I don't think there will be any operator issue because for every SMS, you have to pay, because it's through your SIM card.

And don't some companies only let you SMS to users of their service?

titanium_geek