Here are a few web resources you can use to learn more about Adobe Photoshop Elements.
Photoshop Elements User – this guy is an excellent teacher of Photoshop Elements. He has compiled a few videos about Elements 8, but his past videos are also very relevant as Adobe rarely changes how their standard tools work.
YouTube Search for Elements 8 – The result of a Google search for Elements 8 videos on YouTube. There is some amazing stuff here.
Excellent little Photoshop Layers activity – Although this exercise is not centered around photography, it will give you a good insight into how Layers work.
A nice explanation of levels – Levels is a great way to adjust the brightness and contrast in your images much like you would adjust your bass, tenor and midrange with an old stereo system.
Adobe Effects, Filters, Styles and Artwork tools – How to use the creative tools and features in Elements.
Adobe’s Video Tutorials – A list of Adobe-approved tutorial videos.