There are lots of digital camera reviews sites out there, four big ones, but only three that are the cream of the crop. These three sites give in-depth reviews, comparisons, lots of sample images, and honest comments about digital cameras.
The largest and most comprehensive with a small army of writers and reviewers.
Digital Photography Review
Aimed more towards the consumer end rather than the professional.
Digital Camera Resource
Another with a small army of people who run the site, all dedicated to testing and reviews.
The Imaging Resource
I wouldn't consider buying a camera without first going through these sites in detail about the camera I was interested in, as well as getting ideas on alternatives. These reviews are insanely detailed, including how to use the cameras, the features, etc. Excellent overviews at the end with all the pros and cons. These are the three sites that get quoted the most in the press. They tell you want to look for, what's important and not important, and all highly ethical and will be just brutal in a review if it calls for it, regardless of their advertisers. All have forums for tips, tricks and advice for specific models.