This month's Macworld has a really useful selection of hidden features in Tiger, the new version of OS X:
When you press Command-P to print in Tiger, you'll notice that the Print dialog box sports a new PDF disclosure triangle. Click on it, and you'll see a series of Automator workflows that you can apply when creating a PDF. The Compress PDF option, for example, slims your PDF file by compressing the graphics. However, you can easily modify the provided workflows–or create your own.
(via Plasticbag)