Good sites on the net
www first nature.com
This site covers most nature subjects loads of pictures to compare all british subjects.
www butterfly conservation org
They do loads of butterfly and moths subjects including local sites and what species are there and their flying times.with grid references
Butterfly & Tropical Butterfly
Two pages of common foreign species and moths as well.
RSPB bird identification and British Birds – both good sites.
Failing all else, the Natural History Museum will identify almost anything and you never know you may just find a new specimen and get it named after you. The power of the net is enormous, use it.