Extract a page from a PDF document

You can select a page in the Print dialog, then use Save as PDC in the PDF button at the lower-left. It may give you a larger PDF than you want. Try Combine PDFs
<http://www.monkeybreadsoftware.de/Freeware/CombinePDFs.shtml>
You can delete the pages you don't want. It won't make PDFs larger, as Print may.

Under Windows using Adobe Acrobat Pro you can extract a page from a PDF

Under Mac OS X, using Adobe Acrobat Pro, you can do the same thing.

But there are a few free utilities to do the same thing, as mentioned.
For the Print option mentioned, you can also use the Quartz filters to compress the "printed" PDF.