www.nhm.ac.uk
The Natural History Museum, London. 'Nuff said.

British Geological Survey Fossil Focus
A great site with in-depth information about specific fossils. Very well presented, well-illustrated and informative.

Discovering Fossils (UK)
Locations, resources, shops and events for fossil enthusiasts in the United Kingdom.

Wikipedia Overview of Palaeontology
A useful summary of the subject and its divisions, with links to a multitude of useful topics.

BBC - Science & Nature - Prehistoric Life
An interactive exploration of prehistoric life, with flash games and information aimed at both children and adults.

The National Museum of Natural History (Smithsonian)
Some excellent interactivities and information-rich articles.

National Geographic Archaeology & Paleontology (sic) News
Up-to-date and interesting news about fossils and archaeology.

Enchanted Learning / Dinosaurs
A fantastic little website for the beginner or for young people in need of something a bit simpler. Includes a list of dinosaurs and the various stages and fossils of the Mesozoic era. The childish style does, however, grate after a while.

Download a Dinosaur
A bit of fun! ;)

Jurassic Cliffs
A website focusing mainly on the wonderful geology of the Dorset coast.