Less than a year after the 41st known Mersenne prime was reported
(MathWorld headline news, June 1, 2004), the GIMPS project has
discovered the 42nd known Mersenne prime: 2^2596495 - 1. The discovery was
tentatively announced by GIMPS organizer George Woltman on February 18,
independently verified by Tony Reix on February 25, and the exponent was
reported on February 26. The new Mersenne prime has 7,816,230 decimal
digits, making it not only the largest Mersenne prime known, but also
the largest known prime of any type.

Less than a year after the 41st known Mersenne prime was reported
(MathWorld headline news, June 1,
2004), GIMPS project organizer George Woltman is reporting in an
email message that a new Mersenne prime has been
reported to the GIMPS server.
Addendum: As of February 25, the new Mersenne prime has been verified.
More details will be provided as they become available.