Look for something with a short lag time....
Digital cameras have a big problem where you press the button, sit and twiddle your thumbs for 10 mins until the camerra actually clicks - by which time your subject is 10 miles away....when I was looking a few years ago I found a geeky website buy googling which had all the delays and shutter speed type info on.
IMVHO you don't need lots of megapixels if you just want to shoot and print 6*4's. The more megapixels you have the bigger the file size so the less photos you will get on your memory card. I have a 3mp camera I brought about 4-5yrs ago and routinely use it at the 2mp (or less) setting. Honestly its fine. If I was buying one today I would probably aim for a 4-5mp and no more. Spend the money on upgrading the brand, lag speed and stuff rather than boosting your megapixels.
What do you want the camera for. If you just want to sling it in you pocket the Cannon Ixus and Olympus mju type cameras are supposed to be good. If you don't want to be lugging a SLR type thing around son't bother with it.
Also remember that within your buget you will probably want/need to buy a case, extra rechargeables and more memory.
Someone once told me that its no good spending loads of money on a digital camera if you don't have a good lens to start with. For this reason I brought olympus (cos I associate them with cameras). I think sony are using Carl Zeiss lenses these days too.
In summary. Don't waste money on loads of megapixels, buy a higher spec camera for your money with lower resolution.