P22 rails accept most Insight Tactical lights that fit Glocks: M3 and M6.
P99 right now, only has one Tactical Light choice available: Laser Devices. I'm not counting the goofy looking flashlight you can hang off of the bottom of the BA6 Laser unit, which does fit nice and flush on the P99. The BA6 Laser unit is very nice.
Rumour has it that the new Surefire X lights will have adapters for the P99 rails. And Sidearmor is rumoured to be making an adapter to allow M3/M6 lights to fit the P99.