Spam SMS text messages move into the same realm as email. O2 have issued a warning of a hoax text being sent currently.

“O2 is aware of instances of a chain sms message being sent to mobile users offering a cash credit if they forward the message to further people.
This message is a hoax and is not an O2 promotion as it claims to be. Should customers receive this message we advise them not to respond and therefore not perpetuate the hoax.
O2 is currently looking in to the origin of the message and would like to apologise to customers for any inconvenience caused.”