This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
There are a handful of different free PDF printer drivers. Just Google for that: "pdf printer driver".
Let's back up one step: In what scenario do you need to convert a JPG to a PDF? I'm not saying I can't imagine such a situation; I just want to investigate other possibilities for satisfying your higher-level need.