One new thing that comes with AutoCAD 2010 is that you now can automatically publish PDF files. Previously only DWF files were supported.
Taka look at Options>Plot and Publish
and you find Auto Publish Settings
You can auto-publish on Save and Close as well as get a prompt before the publishing.
The location for the PDF files can either be the drawing folder, a sub-folder relative to the drawing folder named “DWF and PDF” or any other specified folder.
Other settings are if you want to include Model, Layouts or both, creation of single-sheet or multi-sheet files, inclusion of layers, lines merge control and so on.
The AUTOPUBLISH command can also be used to specify some of the settings on the command line.