WASHINGTON — People interested in what their ancestors did in wartime are getting a free look, until the end of the month, at a vast collection of military records online.

The National Archives and Ancestry.com have worked out an agreement to speed the transfer of millions more historical records to the Web and make an existing military collection free for people to see during a Memorial Day commemoration from today through May 31.

Highlights of the agreement being announced today at the archives in Washington:

• Military records containing information on approximately 100 million people can be accessed at www.ancestry.com/military. After May 31, a paid subscription will be required to see them.

• Ancestry.com. has been buying microfilmed copies of the records from the National Archives for several years, putting the documents in digital form and allowing its members to access them online. The documents cover almost every conflict and include draft registration cards from both world wars, images of headstones of Civil War soldiers and Vietnam prisoner of war records, among many other papers.

• The agreement hastens online access to historical records by placing Ancestry.com. technicians in the archives to scan and digitize content. Specifically, the website will be scanning immigration records and death notices of overseas Americans. These records will be available on the site in 2009, said Ancestry.com. spokesman Mike Ward.

• The website will give digital copies to the archives, but the agreement requires the government recordkeeper to wait five years before putting the material on its own online database, said James Hastings, director of access programs at the archives.

• The National Archives keeps hold of military documents in the public domain, and people can see them for free in person. But many records can be accessed only at research rooms of the archives, often just on microfilm, Hastings said.