A Gliding Channel Reference Card has been produced by Paul Ruskin and can be downloaded from Here
This contains a list of BGA Gliding Sites and their nominated frequencies and also a list of the Common Channels and their nominated purposes. This list will be updated as clubs change their frequencies.
You may find it helpful to print these on A5 paper, fold in two, trimming as necessary, Seal in an A6 pocket; and keep in your cockpit.
These channels are first point of contact for cross country gliders.