Oil leaking into spark plug cavities

[mainexile]

I decided to be a good doobie and change the spark plugs on my 06 Canyon 4wd crew cab with the 3.5L 5 cylinder and 150K miles. Cylinders 2, 3, and 4 all had oil in the cavities below the coil packs. Has anyone else noticed this problem? If so, what did you find as the source for the leaks, and how did you correct it?