The simple (and very quick) three step solution to producing high quality PDFs from Pages is the three step process: Pages - PostScript - PDF
1. 'Print' to PostScript
2. Launch Acrobat, then launch Distiller (my computer service technicians insist that Distiller must be active when you convert your PS files)
3. Drag and drop your PS files onto Distiller in the Dock
On machines with OSX Tiger 10.4.10 this process is very quick. On my Intel iMac it takes me less than two hours to process 24 pages of graphics heavy magazine.
At the PDF stage Enfocus PitStop is very useful. It is a pricely piece of software, but worth it. One brilliant feature is that it allows CMYK conversion of the whole file in one go, including PNG files. And it does a thorough checking and correcting of the PDF. You can change text, colours, CMYK percentage etc right in your PDF.
In one episode, a client called me on the mobile phone just as I was about to sign the magazine into press. Although she had given the final approval to her ad she later suddenly realised that the text could be construed in a such a way that she might lose serious money. I agreed with her point, went into PDFs and removed four lines of text right in the finished page.
On another occasion fonts got substituted in an text box. Thanks to Pitstop I could correct his at the very last minute.
Even without PitStop you can achieve very good results, but if you can afford it it's worth its price. Enfocus PitStop retails for $699.