Congress authorized the Internal Revenue Service to spend $35.1 million on its massive project to overhaul its computer systems. The allotment is the first of many, which are expected to total between $5 billion and $7.5 billion over the 10-to-15-year project. The money will be used to complete the IRS' technology blueprint and to expand its Internet service, among other things. The funds were released after the General Accounting Office endorsed the way the IRS and its corporate partners--led by El Segundo-based Computer Sciences Corp.--are taking a step-by-step approach to the project. Congress has set aside $506 million in an information technology investment account, and the IRS will be able to tap more funds if it continues to satisfy the GAO and other oversight groups.