Annotate PDF's and More with Preview

So, your student or colleague has sent you a paper in PDF form and wants your comments. This used to be a pain, for you couldn't write/scribble/cross out on the file, but passed notes back in another form (unless you had invested in 3rd party options, some very expensive). Well, with Leopard, the Preview.app has become supercharged, allowing you to work wonders with pdfs, including adding pages, highlights, notes, and markings, that you can then send back to someone else who can view the comments, even if they're using Acrobat Reader on Windows. Have a look at this recent survey of fantastic new features of Preview in Mac OSX 10.5. Complete list of new and helpful features:

1. Annotage PDFs
2. Delete & Rearrange Pages
3. Merge PDFs
4. Crop & Resize Images
5. Mask (delete background) Images
6. Adjust Image Color
7. Print Multiple Images per Page
8. Add Keywords to Images & PDFs