For DNA testing several lines of Preston have used World Family Tree DNAhttp://www.FamilyTreeDNA.com
The site has in-depth explanations of the process and interpretation of the results. Those tested were assigned Kit Numbers and Passwords to track and access their results by logging in to:http://www.familytreedna.com/Login.aspx
Most of these results were then uploaded to http://Ydna.com
where they can be viewed by all. Go to this site and you can see the latest Preston Project DNA matches and Patriarch information. http://www.worldfamilies.net/surnames/preston/results
(The Bedford, VA group is in Pink)
One of the volunteer coordinators for the Preston site is Angie Preston whose e-mail address is firstname.lastname@example.org
My lineage is
Philip Preston and Mary Unknown died Bedford Co. VA (arrived in Bedford Co., VA 1750's - Don't know where he was before that. Still searching.
Thomas Preston (b.c. 1740) - Mary Ballard of Bedford Co., VA
Joel Preston - Lucy Tate (Revolutionary War Soldier)
Caleb Preston - Elizabeth Majors (Bedford Co. VA to DeKalb Co., TN and Logan Co., KY
Matilda Adeline Preston - William Henry Simmons of Logan Co., KY
Best of luck, Hopefully others of your line have been posted their DNA Y-results and Lineage there.