You don't say what age your children are but around us pre school are only 2 1/2 to 3 1/2 and if that is the case a bit early for Jolly Phonics anyway. I would concentrate on lots of rhymes, action rhymes and stories and their speaking and listening skills. There are lots of fun activities in Phase one of Letters and Sounds however these are more for children of 3 1/2 + but some things like listening walks and body sounds etc might be useful. They need to be really tuned in to listening carefully first. However beginning to hear the sound at the beginning of their name and begin to recognise that the letter makes that sound can be encouraged when finding their name on a coat peg and always when modelling the writing of their name on a picture. If you have children up to school age then Phase One Letters and Sounds (google it) should be useful.