If the image is a little soft the unsharp filter can sharpen it up, but if it is out of focus there is not a lot Photoshop can do. A couple things that might help. Go into channels and click on the individual red, green, or blue, channel. One of the channels may be more fuzzy then the rest (usually red). Use the unsharp filter on that channel. Also you can change the color mode to Lab Color and use the unsharp filter and then change it back to RGB.
Good luck.