"BT's Web2SMS service is a Beta service that allows you to send up to 50 [FREE] text messages per month from a web page."
Basically, one needs to be registered & logged in at their website in order to use this service.
To register for/use the service, apparently one does not have to be a BT customer, but be able to provide a UK mobile phone number - see steeev's post lower down for details (thanks to him for the info).
Frequently Asked Questions:
1. What is Web2SMS?
Web2SMS service allows you to send SMS (or TXT) messages to your friends and family via an easy-to-use web interface. No more fiddling around with your phone, plugging in numbers and letters ... the web interface makes it easy to compose messages quickly.
2. What are the benefits of using Web2sms?
Send messages to one person or many. You can send to any UK mobile or Landline number or select numbers from your BT.com Personal Address Book Type messages easily without straining your thumbs! Send text messages to friends and family while you are overseas.
3. What is the charge for this service?
At the moment the service is in trial and you are allowed up to 50 text messages per month, free of charge. See terms and conditions
4. Why do I have to register my phone?
We ask you to register your phone number so that when we send text messages on your behalf, we can include your phone number within the message. This gives the recipient of the message some idea of who has sent the message and gives them the chance of replying if they want to.
Further questions and answers about Web2SMS can be found at the Beta Forum page.
Terms & Conditions: https://www2.bt.com/smsbeta/selfservice/tandc.do
Apologies if posted before, but I couldn't find it in a search. My very first deal/offer posted :-)