Bitesize Bio has compiled a handy list of free online molecular biology and bioinformatics databases and tools. Among the best are the Online Bioinformatics Resource Collection, which provides links and annotations for more than 2,000 bioinformatics databases and software tools; the BioMed Central databases; the Online Resource Finder for Lifesciences, which provides searches for online resources introduced in peer-reviewed papers in the life sciences; and the Nucleic Acids Research Bioinformatics Links Directory.