The LCD has a protective plastic shield that you can obtain a replacement from Canon for a nominal sum and DIY. Unless your scratches seriously diminish the visibility of the LCD, I wouldn't worry too much about it. Cameras are meant to be used, and if you use it, there will be the normal wear and tear.
As for the protective film, most of what's available out there are of poor quality; they obscure the LCD, and have poor adhesion qualities. After trying several types for my SD700IS and G7, I did find an acceptable high-quality film made by Hakuba/Kenko, but I've yet to find it available outside of Japan.
For recommendations on protective film, you should run a forum-wide search for "LCD film", as it is an oft-discussed subject over in the DSLR section.