1. You'll find this website useful:

http://biology.about.com/science/biology

2. Interesting place for teaching and learning biology:

http://www.microscopy-uk.org.uk/

3. For an interesting classification of living things: An Introduction to the Principles of Taxonomy with a Focus on Human Classification Categories click on:

http://daphne.palomar.edu/animal/default.htm

4. This is a website you must visit as molecular biology enthusiasts. The MIT's Hyper textbook although designed to supplement an MIT Introductory Biology course is one website you must visit to appreciate the effort of the MIT team.