Importing Adobe Acrobat PDF Files
Importing Acrobat files is almost identical to importing EPS files. The Import Options window is identical. This is largely because both formats are closely related.
The only caveat I will add is this: Beware of how large the files are that you are importing. PDF files can become very large very quickly, and large text blocks can take a long time to import and lay out on the Stage. Try importing the flower.PDF file (download it here) to see how this works.
Make sure that your Stage size is the same size as the original PDF file. Normally, this will be letter page size or A4 size because Flash will place the imported objects from the PDF file in the same position as the original PDF file.