Ramblers Association
http://www.ramblers.org.uk

The Ordnance Survey
http://www.ordnancesurvey.co.uk
This site can be used to locate the starting points of walks from their map reference, use the reference without spaces in the box that comes up on the opening page labeled "Place name or postcode.."

North Wales Ramblers Association 

http://www.ramblersnorthwales.org.uk

Wrexham Council Walks Pages 

www.wrexham.gov.uk/walks