The native Mac OS X PDF export (using the Print dialogue) has a default resolution of 300 DPI.
Choose a color printer (even though youÕre going to save as a PDF Ð youÕll need the Color-Sync options)
To access the file-size and compression options of the Mac OS X PDF generator, select ColorSync from the third drop-down box in the Print dialogue. This will in turn present two other drop-down boxes; the bottom one, labeled "Quartz Filter:" allows access to the desired features. There is a built-in "Reduce File Size" filter, but you can adjust the settings, or add a new filter, by selecting the "Add FiltersÉ" option (this will launch ColorSync Utility after most of the printing process is complete, so launching ColorSync Utility from /Applications/Utilities first and setting up your filters is often a better idea.)