its not just megapixels that matter though:
Megapixels don't really affect the quality of the final image, but the size of the image.
For instance, a 2 megapixel camera will take a 6x4 shot.
The CCD which captures the image is also very important as this is what actually sees the light and is what is behind the lens to focus the image to digital film.
So when looking for a camera, it is also good to look at the Sensitivity rating of the image chip that takes the film. A higher ISO number means a higher sensitivity, and this also means you get high speed of shots, since it doesn't need as much light to capture the final image, and so this is good to look out for for someone taking fast shots.
The right lens is also very important of course to focus the light onto the sensor chip:
Even with a good chip, the wrong lens could produce devistating results... like chromatic aberration and vignetting...
These can present themselves as halos of light along edges of objects, or dark patches in the corner of photos, and some good optical lenses can outweigh some of the minuses of a low resoloution sensor by increasing colour depth and detail of the picture, telling you how important this is to get right
I'd say to go for a glass lens and opt one of the big brand name lenses if you can. Panasonics Leica, Sonys Carl Zeiss, or Fuji's Fujinon, though for that price, I'm not sure if you could get one of these lenses or makes though it would make a difference in image quality.
Also look out for the camera lens Focal length, usually quoted as an equvalent value range for a 35mm film camera. A short focal length allows you to capture a wider scene, while a longer length results in a narrower picture angle.
So, the greater the focal range, the more versatile the camera is going to be.
OPTICAL ZOOM BETTER THAN DIGITAL ZOOM:
Optical Zoom is also very important, and this is usually about 3x but 4+ is best, and this type of zoom actually makes the lens move in and out, and change size to aqctaully zoom in, rather than a Digital zoom which will just use the built in computer to stretch and crop a certain part of the image, resulting in a sometimes stretched and dotty image.
So when looking for a camera with these stated, it is best to get one with a better optical zoom than a larger digital zoom which simply emulates the zooming in, and doesn't increase detail but decreases it, and so aim for a really high optical, and if available, you wouldn't need the digital zoom, though you might as well go for it if its there as well, but not instead of.
An LCD screen is also good to look out for to view the images so you can decide if you want to keep them or not, and many have 2.5 inch displays which most video cameras also have as fold out displays, and some allow you to do simple editing of the images before printing them or sending them to the computer.
Digital Cameras are also famous for Shutter lag, and this is what alot of mobile phone cameras suffer from, and other cheaper models, and it is the time in which it takes for you to press the shutter release button, and for the actual picture being taken which is very important for fast shots in which, the action will only be there for a certain amount of milli seconds or less.
The most common way of determing this is how quickly the electonic auto focus works, exposure meters and auto white balance settings, so check the features.
OTHER SETTINGS FOR PROFESSIONAL RESULTS:
With Digital Camera,s most come with alot of manual settings as well as Automatic settings, and these can produce very professional results if used carefully
and really poor ones if not
The S setting for example is good to look for, for fast shots, as this gives you control over the shutter speed, (1/500 for example will get a fast shot nicely in bright conditions with less motion blur)
Alot of features though, are just that, features you won't need, though some can be useful and with that price, I'm not sure what you can get, but you should still be able to get a good camera if you follow some of these guidelines while looking, so don't go looking at just the megapixels for quality, which isn't true, but ends up being the case in most models, though isn't always the case as with cheaper cameras.
It is always best to try them out also, so if you have a camera shop, a good test try of a few might help you choose for web buying if thats what you would do. (Some of the values stated above are actaully stated on the lens on the camera itself, like for example the sensitivity, and focal range)
i hope this helps