Skim

Skim is a program that allows you to view PDF files comfortably. Like the Mac OS X's Preview, Skim offers a search, presentation and a screenshot function.

In addition, with Skim you can save PDF Bookmarks, provide them with notes and highlights and convert PostScript files (PS) files into PDF.

Skim also supports PDFsync, AppleScript, Spotlight and the Apple Remote Control.