I think this has come up before but there appears to be more films available now under the deal. The following films appear to be showing at most cinemas:
Gnomeo and Juliet
The Itch of The Golden Nit - followed by Wallace and Gromit in 'A Matter of Loaf and Death'
Tickets are £1.25 per person (Child or Adult) which seems a great deal. There are also other films which look more cinema specific. You can save on the booking fee by booking at your cinema or just turning up. Although obviously this allows for the possibility of some very unhappy little faces