NXPowerLite will compress PDF, Microsoft PowerPoint and JPEG files simply and effectively, making them easy to email as attachments. It is especially effective on files that don't zip well. You can optimize and automatically attach files to a new email by selecting the files and using 'Optimize and email' in Finder.
NXPowerLite will effectively shrink files that don't usually reduce with Zip compression. As an added advantage, optimized files stay in the same format - a PDF remains a PDF. It will just be much smaller.