At work, often we will receive PDF scans of engineering plans for projects that adjoin or otherwise impact work we're doing. There are times it is useful to put some of these sheets in AutoCAD, so I've come up with the following method since I can't put PDFs inside CAD files, but I can put TIF or JPG images in.
If you have Microsoft Office, one of your printers should be "Microsoft Document Image Writer." Select that as your printer and print to a file. It will open up in Microsoft Imaging as a *.mdi file. Using that application, save the document as a *.tif file. At this point, you have a raster image you can actually do something with.
I would also like to echo Ken's advice to avoid copying copyrighted items, except for your own personal use.