Your Family Tree

http://www.ysearch.org/

If you have tested with a DNA testing company you may be interested in Y-Search.

Y-Search is a free website sponsored by Family Tree DNA whereby any one who has tested with any company can compare their DNA markers to those who have taken a test with a competitive company.

Basically one registers, uploads their results and the results is compared to other who have also uploaded their results no matter which company they tested.