These are sites that allow you to upload your photos and share them with the world. The best aspect of these sites for someone looking to get into selling stock photography is the photo critique features. The sites listed first are the ones with the most active photo critique areas.

Pbase - PBase Photo Database - Photo Hosting - Photo Sharing - Web Photo Galleries

Flickr - Flickr is almost certainly the best online photo management and sharing application in the world. Show off your favorite photos to the world, securely and privately show photos to your friends and family, or blog the photos you take with a camera phone.

Acclaim Galleries -

Model Release Apps for Apple's iPhone - Links to apps that allow creating, storing and disseminating model releases and property releases on the Apple iPhone.