Katey,
I save each download in a folder by itself inside a folder named for the website. I also rename my kit folders with the designers name first then kit name (ImaDesigner_mykitname). That way everything by one designer is grouped together. People have different ways of organizing their digiscrapping stuff. You might check the tutorial section for sugestions. I know some people organize by type of file (a folder for papers, buttons etc.) I just like to keep everything together with the Terms of Use and so I know who to credit.