Terry has a great list of all the online photograph-sharing-services, but has forgotten to mention one of the most important. I was going to simply leave a comment, but I got a little carried away with my response:
One more to add that really should go at the top of your list, even before flickr.com: http://www.redbubble.com.
This is an Australian-born site, out of Melbourne with an international presence. Simply put, it’s a site that allows users to upload and sell their BEST art. Then the technerds at Redbubble looks after the finance, card-making, lamination and framing and distribution. It’s free and really easy to use.
As you can see, I’m a big fan! I’ve been a registered user since April this year (thereabouts), so I feel like a veteran and part of the furniture. I encourage everyone to get over there, take a look, even join up if you feel it suits your art. But most of all … BUY SOME ART!.
Particularly from my collection. I shoot everything from Australian landscapes and horizons through to farmyard rusting paraphernalia, from water-scenes through to abstract moments, from antique furniture through to historic architecture, from formula one racing through to classic cars of yesteryear. I am a part-time freelancer (because I still need my day-job for some security!)
Yes, a self-serving article. When you are as passionate about photography as I am, you’d do the same.