If you're looking for greater PDF editing capabilites than Preview, you should check out our PDFpen:

PDFpen features:

• Show PDFs in single, facing-page, multi-page, and multiple facing-page views


• Fill out and save PDF forms


• Create cross-platform fillable PDF forms (requires PDFpenPro)


• Re-order pages in a PDF by drag & drop


• Insert pages from one PDF into another (drag & drop or copy/paste)


• Remove pages from a PDF


• Overlay text and images onto PDF (for example, sign purchase orders by applying signature image)


• Use with pagesender for a complete fax turn-around solution


• Automate PDF manipulations with AppleScript


• Available in English, Japanese, German, Italian, and French