In the UK the British Dragonfly Society maintains a website with details of dragonfly recording in Great Britain, including useful papers on habitat management and creating ponds for dragonflies.
Dennis Paulson's site at the James R. Slater Museum of Natural History, University of Puget Sound is worth visiting - check out the scans of NorthWestern USA dragonflies.
The Digital Dragonflies site has details of how to scan live dragonflies using a flatbed scanner, and some amazing images - look at the dragonfly catalog and damselflies of Texas.
George Mahoney in Milton Keynes has a good personal site with photographs and sites for dragonflies in north Buckinghamshire in England.
The Lincolnshire Wildlife Trust maintains a site with photographs and details of distribution of dragonflies within that county.
Atropos magazine for Lepidoptera and Odonata enthusiasts in the UK.
Dutch dragonfly association (Nederlandse Vereniging voor Libellenstudie, NVL) this site is mostly in Dutch and aims to unite amateur and professional researchers. A checklist of the European Dragonfly fauna is provided.
Dutch Dragonflies - an alternative photo and video site of the dragonflies of The Netherlands
Robert Thompson's photographic website this site has a small selection of excellent images from Robert Thompson's extensive photographic library which includes dragonflies, butterflies, moths, orchids, birds and landscapes.