When you use Distiller, go to Settings ... Job Options ... Fonts and make sure that "Embed All Fonts" is checked.  If you are using a different PDF writing method, look for an "Embed All Fonts" option.  This prevents the common problem of "dithered" output of fonts.

Note also that you can use Settings ... Job Options ... General to choose to write a PDF file that is compatible with Acrobat 3.0 instead the 4.0 default.  This may be useful since many users have not yet upgraded their Acrobat Readers.