When Rob Haggart talks, stock photographers listen - as do a lot of others. He’s the former Director of Photography for Men’s Journal and Outside, and the blogger who created A Photo Editor, a widely read blog on photography. He’s created a very lengthy list of stock photo agencies, and it’s something every stock shooter should study before making a submission to a site.
Not unexpectedly, Getty and Corbis are at the top of his list, but interestingly, Alamy and Photoshelter are hard on their heels. He also lists boutique and specialty agencies, but the most interesting list is his “crap” list - comprised of microstock sites.
Here’s his list: http://aphotoeditor.com/2008/02/27/stock-photo-agencies/
Not only a great list of places to submit, but a list of places to avoid. There’s enough good agencies listed to keep a stock photographer busy a long time.