It appears as if Nikon has introduced a new Micro (macro) Nikkor lens designed for their DX format lineup of cameras. The new AF-S DX Micro-NIKKOR 40mm f/2.8G is a compact micro lens with a 1:1 magnification ratio. It features Nikon's SIC (Super Integrated Coating) to reduce flare, a built in SWM (Silent Wave Motor) for quick and quiet focusing, CRC (Close-Range Correction) technology for superior focusing at close distances using floating lens elements plus a M/A (manual/auto) focusing switch to quickly turn the ring to manual focus.
This is Nikon's second Micro-Nikkor in the DX lineup, after the AF-S DX Micro-NIKKOR 85mm f/3.5G VR which was announced third quarter 2009. The main differences between these lenses would be their focal length, physical size, aperture and the lack of VR in the 40mm. Another important factor of the 40mm is that it's priced at $279.95 USD, a full $250 less than the $529.95 USD 85mm Micro.
The 40mm (left) compared to the 85mm (right)

These images are not to scale. As you can evidently see, the 85mm is quite a bit larger.
The MTF charts compared. Again, 40mm is left and 85mm is right.

Looking at the lens design, you can see that the 85mm (right) features 14 elements in 10 groups and offers an ED (Extra Low Dispersion) element (shown in yellow), while the 40mm (left) features only 9 elements in 7 groups with no ED element. Another point to note is that the 40mm offers only a 7 bladed aperture diaphragm, while the 85mm offers a 9 bladed diaphragm, for smoother better rounded bokeh.

This lens seems like a bit of an oddball, it came as a bit of a surprise and the 40mm length is a bit strange for a micro lens. Of course, when you factor in the 1.5 crop, it becomes 60mm which is a much more common focal length, good for macro shots of flowers or as an all-purpose prime.
Access the lens' web page
here.
Some sample images...
f/2.8
f/3.2
f/4.2
View the full list of sample images
here.
So what's your opinion on this new lens? Would you be interested in buying it when it hits the stores in August?
I hope that I gave you a little more information about this new lens. If you have anything else to add or want to comment on something, post it down below.
Thanks,
-Evan