Credit Carlos Canto for this plugin which will import a PDF file with multiple pages into a single Illustrator file, placing each page on an individual artboard. Note that you can save the Illustrator file back to multi-page PDF format. Amongst other things, this is useful as an alternative to printing out online forms provided as PDF files. Pull your forms into Illustrator, add text and superimpose images and/or digital signatures, and save them back out. Save some trees.