The headright system was used in other colonies, but only in Virginia have the records significantly helped researchers find ancestors. However, I did also come across copies of reports of headrights at the archives and information services division at the Texas State Library. This collection of 18 boxes of headright reports from many of the counties of Texas from 1836 to 1855 is available for study.
In Virginia few ship records have survived, leaving only the headright records to imply passage was made to the new world. One bonus is that, if you can find out where in England the patentee (the one whom paid for the passage) lived, you can possibly narrow your search for the person for whom he paid passage, as they sometimes lived in or around the same geographical area. All social classes, including gentry had headrights. Often they were the second or third sons of a gentry family. It was incorrectly believed that a majority of passages were paid by ship captains.
You need to know that there are some assumptions which can not be made while studying headright documents. For example, a headright agreement may have been signed at a different time than the actual voyage was conducted. In Bob's Genealogy web site, Robert W. Baird did an analysis of Headrights in Surry County, Virginia. He found that the average interval of time between the issuance of the headright and the issuance of the patent was roughly five years. Some certificates were issued as long as twenty years later. Often travelers to the new world returned to England and sailed back across the Atlantic several times and each time another headright patent was registered. Thus, a repeating name in the headright list may be the same person. Also individuals whom arrived in Virginia received receipts or certificates of transportation. Some sold such receipts to others for products or land. Thus, the name on the final grant of land may not have been the original immigrant who crossed the ocean. Fewer than 50 percent of the headright names mentioned in the county court house records were from the resulting grants.
In my search for my Owen ancestor, the Owen association has compiled a list of the 119 Owen headrights, 97 of which were listed in the counties and the other 22 showed only a river or creek as the site of the grant. These names were culled from three of the 7 volumes by Mrs. Nell Nugent's Cavaliers and Pioneers: Abstracts of Virginia Land Patents and Grants. It covers a 100-year period with 86,000 persons listed. The Virginia State Library had published three of these volumes by 1979. The information can also be found on CD at Genealogical.com. Headrights are found in public records known as "Virginia Land Patents". A number of these records were published by George C. Greer in 1912 entitled, Early Virginia Immigrants 1623 - 1666.
If you are searching for your earliest ancestor and wondering when and where he entered America, don't forget that there were also many prisoners sent from England to America. One additional source is the Complete Book of Emigrants in Bondage 1614 - 1775 by Peter Wilson Coldham and published by Genealogy Publishing Co. in 1988.
In England they not only transferred criminals but also inmates of London Bridewell (an institution for vagrant and orphaned children.)
If you find your ancestor to have arrived in or around 1649, he could have been one of many defeated Royalists who were forced to move to America and settle in many of the Atlantic coastal regions.
And lastly, another source is The Bristol Registers of Servants sent to Foreign Plantations 1654 -1686. Many individuals were contracted out and there were some organizations which acted like a modern temporary employment agency which matched colonies and communities which needed skilled labor.
I hope this is helpful. There is a lot of information on the Internet about headrights. Many articles are confusing and I myself had to sort out what they were talking about.