you can get 30 free text messages a month if you sign up to O2. www.o2.co.uk
you don't have to be an o2 customer but you do have to provide a mobile number
alternatively there is a place called cardboard fish SMS www.cbfsms.com
who offer unlimited free text messages, but their service is frequently offline because of high demand, and it doesn't tell you it's offline untl you've written the message and gone through the screens.
I've replied, because I suppose you'll get an email now I've replied, and also I don't really email random people from forums also if you don't come back to check your post you couldn't have been too desperate to know...