The BTO (British Trust for Ornithology) run a range of volunteer surveys.  To find out how to get involved in any of these, follow the links below:

Breeding Bird Survey (BBS)

Garden BirdWatch (GBW)

Garden Nesting Survey

Nest Record Scheme

Ringing Scheme

Waterways Breeding Bird Survey (WBBS)

Wetland Bird Survey (WeBS)
 

BirdWatch Ireland also run a range of volunteer surveys.  For more information, visit the BirdWatch Ireland surveys and projects page or follow the links below:

Garden Bird Survey (GBS)

Countryside Bird Survey (CBS)

Irish Wetland Bird Survey (I-WeBS)