Here are some great links by Larry Ferlazzo.
There's a good web2.0 teacher toolkit here at ChangED, by Angela Cunningham.
This is a collection of webquests organised by 9 big museums and gelleries in England.
Twurdy is a search engine based on Google BUT it has a readability score, from 0 (easiest to read/simplest language) to 1000. Seemed effective from what I saw.
Using Technology to Support Creativity and Critical Thinking has a good selection of ideas.