Flickr is run by Yahoo and is pretty good, but sometimes a little hard to navigate. Picasa is part of Google's empire, and so you can set up an account there using your Gmail (which I know most of you have). Whichever you choose is fine — I would suggest playing around with both for a little while first before choosing.
Keep in mind that you may want to use this web album to showcase your work in the future.
Post a link to your web album as a response to this post before class on Friday. You do not need to upload any photos to it yet.