When you're ready for the cutting edge in genealogy research, these sites can help you jump into the gene pool.
GeneTree
This innovative site, still in beta, combines DNA and social networking. Although limited to mitochondrial test results so far, its mapping of DNA results is the best we've seen. You can order test kits here, but you can search for you DNA matches no matter which lab you used.
Sorenson Molecular Genealogy Foundation
This nonprofit organization is dedicated to building the world's foremost collection of DNA and corresponding genealogical information. To date, its database tops 70,000 DNA samples with family trees from around the world.
YSearch and MitoSearch
These sibling databases from Family Tree DNA let you search for Y-DNA or mtDNA matches no matter whom you tested with. At Family Tree DNA's site, you can see if your surname is among the 74,355 in the company's client database.