Small Business Lending Improvement Act of 2005 - Amends the Small Business Act to establish within the current Preferred Lenders Program operated by the Small Business Administration (SBA) the National Preferred Lenders Program, under which a participant may operate as a preferred lender in any state if the lender meets eligibility criteria established by the SBA. Allows each approved participant to make loans for up to two years under the program.
Increases: (1) to up to $3 million the maximum authorized SBA gross loan amount for small businesses; and (2) the FY2006 authorization of appropriations to the SBA for such loans.
Directs the SBA Administrator to establish an alternative size standard (measuring the size of a business for purposes of eligibility for small business loans) utilizing the maximum net worth and net income of the prospective borrower as an alternative to the use of industry standards. Requires, in the interim, the use of an alternative size standard regulation.