2Can Bioinformatics Primer -- website from the European Bionformatics Institute that provides a basic introduction to bioinformatics as well as guidance on database choice & uses

Kimball's Biology Pages -- Another on-line introductory textbook (based on a hardcopy version by John Kimball) with a handy alphabetical search feature

Molecular Expressions Optical Microscopy Primer -- a wealth of information about the theory & practice of microscopy

Virtual Cell -- lets you slice & dice a cell on-line and find out more about its innards

Cells Alive -- Full color, pretty pictures of a miscellaneous collection of cells & their components

Blazing a Genetic Trail -- Howard Hughes Medical Institution site on human genetics

The Interactive Fly -- Find out all you ever wanted to know about Drosophila developmental genetics

WebGURU -- a wide-ranging guide to the Undergraduate Research Experience; created by a consortium at Northeastern University