Links to other websites that you might find useful: -

Training
Mary Ann Nester
Acorn Dog Training
Learning About Dogs

Media
Agility Net 
Agility Eye

Shop
Agility Warehouse
RVA (suppliers of agility equipment)
Clean Run
Crosskeys Books

Shows
Dogs in Need Agility Society
East Midlands Dog Agility Club 
It barks
UK Agility

Organisations
The Kennel Club
Agility Club 
British Flyball Association
Association of Pet Dog Trainers

Nutrition
UK Barf 

Just for fun
Agility movies
Agility Bits