"PDF is everywhere",
says Joshua Marinacci of Sun Microsystems on his blog.
Joshua is on the Swing team at Sun; he recently co-authored O'Reilly's Swing Hacks.
Flying Saucer looks cool
He also leads Flying Saucer, a very interesting looking project for PDF generation. Flying Saucer is a Java library that lets you generate PDF from XHTML and CSS inputs. I'm planning to check it out for possible use in my xtopdf toolkit. I took a look at the code for the Flying Saucer examples, its quite small for what it does - looks like a well-written library.