Original solo monster guidelines: x5 hit points (x4 for heroic tier?), +2 to 2 or 3 defenses, 2 APs, +5 to saves
New (DMG2) solo monster guidelines: x4 hit points, 2 APs, +5 to saves
The only change is a decrease in hit points and no boost to defenses. If you own MM2, MM3, MV, or the Dark Sun...