Advanced Preservation Information Links
Preservation Law and Finance
The National Historic Preservation Law of 1966 is a very important law for preservation.
As is the Section 106 Review Process.
In terms of government documents, the U.S. House of Representatives Internet Law Library will give you some info. (It appears that this is some sort of archived version - may not be very helpful.)
(Computer archive: The U of VA Law Library On-line Catalog may help. After entering this TELNET site, type in library.)
Tax Incentives can be a major starter for projects.
Or the Maritime Heritage Grants. (Although it appears they are out of money...)
There is also the Challenge Cost Share Program. These are all government grants and tax incentives. The government is the primary source for money easements for preservation.