One of the best things about Mac OS X is its built-in support for PDF files. Instead of testing your sanity while you wait (sometimes it can seem like forever) for Adobe Acrobat to open a PDF file, you can use Preview.app to open them up quickly. However, built-in PDF support allows you to do other neat things as well. Here are five of my favorites.
At the top of the list is the ability to create a PDF from almost any document. Whether it's a Word or Pages document, a spreadsheet, or a Web page, in most instances you'll be able to create PDFs out of them. Many Windows users print to a PDF printer in order to create a PDF file, and in a similar manner, creating PDFs on Mac OS X involves selecting the print option from the app that you're working in. Within the app, click on "File" and then select "Print." Then, you'll be presented with a dialog box with a "PDF" button on the left. Click on this button and select "Save as PDF."
Once you've created your PDF, you can annotate it. Open up your PDF in Preview.app, click on "View," and select "Show Annotations Toolbar." After doing so, a toolbar will appear on the bottom left of your document. Alternatively, the toolbar will also be displayed if you select any of the annotate options under the "Tools" menu. Annotations include the ability to create text boxes (useful for filling out forms), add notes, or highlight and create shapes (among other things).
You can also move pages around within Preview.app (like rearranging the songs in an iTunes playlist). Simply choose "Contact sheet" or "Thumbnail" view from the sidebar, and then drag and drop your pages as you see fit.
Let's say that a couple of pages within a PDF interest you, and you want to revisit them later. To do this, click on "Bookmarks" in Preview.app and select "Add Bookmark" (or use the Cmd+D shortcut). One of the neat things about this feature is that, even if your PDF isn't open, you can still access your bookmarks.
I've made no secret about my fondness of Preview.app's image editing ability, and this extends to PDFs as well. One neat image editing feature for PDFs is the ability to select an area and create a new image based on this selection. To do this in the PDF, click on the "Select" tool, select an area, and copy it. Then, in Preview.app, click on "File," select "New from clipboard," and voila, your selection is in a new document. This document can be saved in a variety of formats, including PDF, JPG, and PNG.
PDF parsing and rendering are core features of Mac OS X and iOS. While providing for native support for PDF files, it also served as the foundation for the recently released Web-based jailbreak for the iPhone.