A text message is being sent to vodafone users, it will pop up on the phone
as a normal text message "Text Message Received".  If the user accepts this
the message will be displayed with the number"901101".  Vodafone suggests
that the user cancels it by either using the "C" button (on a Nokia 5110) or
by clicking "Back" on the 6150s.  If the message is opened it will
automatically dial an American agency @ 50 pence a go.  
 
Vodafone have advised that they are doing their best to eliminate this but
as a precaution users will have to follow the above instructions.