Here are some useful links for researchers studying genetic variation:

The National Human Genome Research Institute www.genome.gov

The Institute for Genomic Research www.tigr.org

The National Center for Biotechnology Information www.ncbi.nlm.nih.gov

Ensemble Database www.ensemble.org

NCBI BLAST www.ncbi.nlm.nih.gov/blast

GeneSNPs at the University of Utah www.genome.utah.edu/genesnps

The SNP Consortium http://snp.cshl.org

UC Santa Cruz Genome Bioinformatics http://genome.ucsc.edu