Picasa Web Albums is a tool used to upload and share your photos. (Note it is not the same as the stand alone Picasa software used to organize photos on your computer.) Photos loaded in Picasa Web Albums can be accessed from any computer connected to the Internet.
Picasa Web is now an enabled application in Clemson's Google Apps for Education. You may log in to http://g.clemson.edu using your Clemson Google Apps for Education login and password. Then open another tab in the same browser and go to http://picasaweb.google.com.
No. Picasa Web Albums is a free application.
No. Picasa Web Albums is completely online. You just need to have a web enabled browser to create and share Picasa Web Albums.