GEnerating PDF's

Hi List I'm investigating different possibilities to generate printable and read-only documents, and the "best" method seems to be generating PDF's, however, I have NO experience with working with PDF's, and the examples in the manual only list a simple "one-liner" text pdf. Where can I find more material that will explain in layman's terms how to generate pdf's from various sources. As example, I'd like to generate PDF's of a webpage "on-the-fly" or even from data in MySQL tables. It seems that you need to provide the pdf generation process with the co-ordinates and size of each "element", but it is the location of the "elements" that I have trouble with, ie. what is needed to define each element? Thanks for the help.