Conlin, who is based in Des Moines, said in a separate interview Wednesday that the plaintiffs and Microsoft had held "sporadic discussions for quite a long time" about a possible settlement. "But we really started to close the gap on Sunday, and we finalized the settlement at about 6 p.m.," she said.

Last month, the plaintiffs posted , including letters, memos and e-mails from Raikes and other Microsoft executives, on a public Web site called www.iowaconsumercase.com. That site wasn't accessible Wednesday, as would-be visitors were asked to enter a username and password. Neither Conlin nor Wallis would comment on whether the site was being taken down as part of the settlement deal.

Microsoft was hit by a spate of state-level class actions in the late 1990s following the U.S. Department of Justice's federal antitrust lawsuit against the company. The Iowa case is one of only two state suits that have gone to trial thus far. A case in Minnesota was settled in 2004 after two months of trial, with Microsoft agreeing to pay a total of US$175 million to customers in that state.

The Iowa plaintiffs had been seeking up to $330 million in damages, alleging that customers had overpaid for software because of anticompetitive practices by Microsoft. The terms of the settlement aren't being disclosed pending an April 20 court hearing on the proposed deal, and both Conlin and Wallis declined to say how much money Microsoft will pay as compensation to the individuals and businesses that qualify as members of the class represented by the lawsuit.

But Conlin said the agreed-upon amount is roughly proportional to the compensation paid in Minnesota, based on the number of customers and their software purchases. In Minnesota, the overall population is about 50% larger than Iowa's. But the period for eligible purchases of Microsoft products was three years shorter than it was in Iowa.