In reply to Bike-Mum:
There's only a small amount of Sport Climbing on Anglesey.
There are 2 guidebook options for the coastal sport - "North Wales Limestone" (includes the Benllech/Moelfre sport areas and also some Trad routes and venues) and "A55 sport climbs" (2nd edition just published so more up to date?). Both also include sport climbing crags such as Castle Inn Quarry, Marian Bach, Penmaenhead, Penmaenbach, Dyserth Crags etc.
You may also want to consider "Llanberis Slate" - the Dinorwic quarries have a large number of sport climbs and aren't covered by the other 2 books.