This has been coming for a while, but the day's finally here: Michelin has announced its departure from Formula One after the 2006 season. The FIA claims that the teams were clamoring for a single tire supplier, and thus ruled that there would be only one for the 2008 season, so Michelin bailed on the party early, leaving all of the toys to Bridgestone, who affirm that they're staying in the game. [Thanks to John for the tip.]
Michelin to leave F1 after 2006 [TSN.ca]
Related:
McLarenn Mulls Switch to Bridgestone [Internal]