Nice edit Mike. I can see you have played with the contrast which is something I really should have done more. (you should see the original, its really lacking - it was a fair increase just to produce my version!)
How did you get it to look so much sharper though?
First of all I opened the image using raw converter in bridge. (yes you can do that!) I changed the images color temperature to a more pleasing hue. I knew the squirrels belly was more of a grey or a white than a blue. Then I opened it in photoshop.
I had noticed that your subject was a bit softer than the grass in front of it. To correct this I used a series of techniques to enhance the sharpness without introducing more noise. Using Genuine Fractiles I scaled the image up to 2000px high. I do this instead of using the standard PS resizing because it doesn't make the image blurry. It will however reveal detail you hadn't noticed before. (it doesn't create more detail though you may think so at first) I then used Noise ninja with custom settings, not to remove the noise but to enhance the image by use of a subtle contrast sharpening. (not the same as normal sharpening) The effect is very pleasing and it brings out the detail without enhancing the photo noise, jpg artifacts, or introducing halo effects on subject edges.
Just looking at the levels In PS I saw that the photo was underexposed a bit so I corrected it using a combination of "levels" and legacy contrast slider. I noticed your comments about contrast so I made it extra contrasty without loosing image detail.
The squirrel was still looking a little soft so I used the patch tool to select him. Adding a feather radius of 5px I was able to add additional sharpening without creating an obvious boarder. Feathering just makes the transition nice and smooth. I think I used smart sharpening settings of 70 and 2.0 "lens blur".
Finally I resized the image down to 600px high for web save. The image immediately appeared sharper and more pleasing. Much more so than if I had done all of these steps without upressing the image first with genuine fractals.
This was all done using my personal techniques and tastes. Its a lot of work and it really is a poor substitute for a in focus shot or a sharp lens. Thankfully the tools are available to help us enhance our images when things do not go according to plan. Squirrels are fast and hard to keep up with!