Photoshop.com

If you cannot afford the full version of Photoshop and have not broken down yet to purchase Elements, Photoshop.com is for you.  Signing up allows you the ability to store up to 2Gb of pictures using the free service.  More disk space is available of course at a monthly charge.  No unlimited plan is available yet.

Photoshop.com offers a watered down version of elements, allowing for simple adjustments and cropping.

One of the coolest features is the ability to connect to your facebook, flickr, photobucket, and picasa assets.  I think this feature has the most potential for extensibility.  Although it does not persistently store your login information for immediate display of the assets, it is really cool.