Science Gateways

Intute: Science, Engineering and Technology is a free online service providing you with access to the very best Web resources for education and research, evaluated and selected by a network of subject specialists. It covers the physical sciences, engineering,computing, geography, mathematics and environmental science.
(Formerly EEVL, PSIgate and BIOME)
Scirus is the most comprehensive science-specific search engine on the Internet. Using the latest search engine technology, Scirus searches over 200 million science-specific Web pages.