The GenealogyBlog pointed me to this article by James M. Beidler printed in the Lebanon PA newspaper.
The important points are:
The warrant registers serve as the basic index to the original land warrants, surveys and patents for about 70 percent of the land in Pennsylvania, covering the dates 1733 to 1957.
A warrant is the first step in the state land process, resulting from the purchaser’s application for a quantity of land (usually expressed in rough terms at this stage — 100 acres or 250 acres, etc.).
After being granted a warrant, the purchaser then proceeded to have the land surveyed — meaning that a drawing was made showing the boundary lines, corners and adjoining landowners of the property as well as the lengths and angles of each boundary line. Many of the written descriptions of the surveys use such interesting landmarks such as stones, black oak trees or posts.
After the land was surveyed, the buyer paid the appropriate fees and the purchase price of the land, and had a patent for the property recorded with the state. It was with this patent (essentially, an “original deed”) that clear title passed from the state to private ownership.
The newly Internet-accessible warrant registers are arranged alphabetically by the surname of the person who got the warrant (known as the warrantee).
More specifically, entries are grouped by the first letter of a person’s surname, and then arranged in rough chronological order by warrant date.
The geographical area covered by any particular warrant register includes the boundaries of the county as it existed at the time of the warrant. For example, a 1765 warrant for land now in Lebanon County would be entered in the Lancaster County warrant register.
To access images of the warrant registers online, use the State Archives Web site at the URL, http://www.phmc.state.pa.us/bah/dam. Click on the “Record Groups” hyperlink; then Record Group 17, “Land Office”; and finally look for the “Images” link under No. 17.88, “Warrant Registers With Green Covers, 1733-1957.”
This link will take you right to the Land Records page. You will have to click on the County of interest, then search by surname (which are grouped by first letter, but are not alphabetical.
Remember that these are the original grants of land by the State, and not "land records" that show passing of land from one person to another via deeds.