Pretty sure you could practice with, say, a word processor. Not the optimal tool, but they usually are somewhat easy to use and come with templates. CCP (allegedly) has professional artists employed, so your first try doesn't need to compete with what they produce. Usually you cannot break your computer with that stuff, so you can fiddle as much as you want with them.
Is worth repeating: Whatever you can put on paper, you can put on PDF via CutePDF, PDF Maker and other PDF printers. At least a few of them even allow to add background images and text after the file is sent to the PDF software (i.e. "TOP SECRET" "stamps" and things like that).
So sure, you can use Adobe Photoshop, Adobe InDesign and Adobe Acrobat Pro. Or you could as well use GIMP (bitmap editing), Inkscape (vector graphics), Scribus (layout) and PDFCreator (conversion to PDF).