As others have said, you can't really retrieve an out of focus or blurred photo. But you can improve it enough to still enjoy the picture. (According to the movies, the CIA and NSA must have some pretty nifty ones, but if so, they're not sharing.)
There are lots of simplified photo editing programs out there, as other posters have listed. I'd try the free ones first and see if they're intuitive for you. I've heard really good things about Picasa from acquaintances. Personally, they all annoy me with their indecipherable little user-friendly icons and I prefer the control of Photoshop.
With ANY photo-editing program, there are a couple of controls you should try. First, open your image and save it with a different name (I add a "c" to the end for "corrected"). That way your original is unharmed and you can try everything.
You mentioned brightness and contrast as well as focus. The single best thing you can do to improve dull or dark photos is to adjust the Levels (this makes your whites white and your blacks black and balances everything out in between). Now I know that sounds like Greek, but look for a button in whatever photo editing program you choose and try it. The brightness/contrast adjustments are a simplified version of the same thing. In Photoshop, Levels presents you with a histogram (a chart that looks like a heart-rate monitor)... there are three little arrows below. Click on the one at left and drag it in (right) to where the first black jagged peak starts. Click on the one at right and drag it left in the same way. Thsi will help enormously. This is exactly what the brightness/contrast buttons do, but with less control. If the photo is overall still a bit dark, drag the middle arrow to the left until you like the result.
Unsharp mask is a little complex, but try the Filter/Sharpen Edges function and the other sharpening options to "crisp up" a soft focus or blur.
Now, having said all that, with a decent camera like you have you shouldn't be getting blur. Try an ounce of prevention and see what you can do to fix the blur problem:
1) If it's always done it, consider the fact that digital cameras pretty much always have a bit of delay when you take the picture (shutter and focus lag) that film cameras don't. Hold it very steady (or brace it on something) when you take the picture and HOLD it there for a few seconds after to make sure you're not putting your arm down just as it's capturing the image. The default setting is probably to focus when you depress the shutter release (button), and it may take a while to get it right.
2) Try half-depressing the shutter release to lock the focus before you take the picture (but if the subject is moving toward or away from you this won't work either). If what you want to have in focus isn't filling about 1/4-1/3 of the MIDDLE of your scene, then this is essential (if you want, say, your dog on the left and the beach on the right, frame you picture with the dog in centre, half-depress the shutter release, and holding it there, recompose your picture to the right before taking the picture).
3) Avoid taking pictures at full zoom, as this makes any shake worse. If you have your digital zoom enabled (I'd turn it off) and you take pictures at full zoom, you're only getting about half the resolution, because it's cropped the rest of the pixels out to make the subject bigger, thus they'll often look fuzzy.
4) Avoid taking pictures in very dark areas, or at least make sure you have the flash on. Any combination of zoom or no flash and dark area often = poor focus.
5) Try to look through the manual or take it to a shop with a nice sales guy and make sure it's on default settings and normal shooting mode.
6) You might try changing the focus method to "continuous" if it has that option, so it's continually focussing on whatever's in the middle of the frame. This will make more noise and drain your batteries faster, but cut down the wait time for it to focus before capturing the image.
7) If nothing else works, ask someone with a really big, expensive digital to take a few pictures with it. If a photo buff can't get a good shot with it, then I'd talk to the store where you bought it about a replacement. At least then you know if it's your method or the camera.
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