The closest iPad 2 vs. iPad 3 side-by-side comparison so far.
Looking at the iPad's Retina Display Under a Microscope : Read more
Looking at the iPad's Retina Display Under a Microscope : Read more
Hell a camera can catch the regular DS lite pixelsMathis has got some great photos of a range of different displays under the scope. He's done everything from the PS Vita, to the 3DS, the iPod touch, and the Kindle. Check it out here.
Device uses PenTile technology. Its pixels consist of only two sub-pixels instead of three and the claimed pixel density is only achieved using subpixel rendering. In any case, the ppi numbers are not directly comparable.