Research-It! This is a great site for general tools, from dictionaries and thesauri (?) to maps and language translators.FunkandWagnalls.com. Encyclopedia, dictionary, and more.
Internet Public Library. A storehouse of all sorts of information. I found their Word and Phrase Origins section very helpful.
Guide to Laboratory Report Writing. A well-organized site presented by Illinois Institute of Technology. Thought I was anal retentive about reports?Writing Guidelines for Engineering and Science Students. I highly recommend this site for all engineers, not just students. Think you're a good writer? Then try their writing exercises, located in the Site Links!
Online Resources for Scientific Writing. This site has some very good information on report writing techniques, as well as scientific writing style.