Cheat sheets can be very handy while quickly referring to a technology one uses on a daily basis, although they can be tough to read (and write!) if the technology is very extensive like JPA. Fortunately, the changes in JPA 2.1 are definitely small enough to fit on a cheat sheet. Note, just because the amount of changes are small definitely does not mean they are not important. In fact, most of the changes in JPA 2.1 have generated a good deal of interest in the community and are already proving to be well received. Very fortunately for us, Thorben Janssen has gone through the effort of putting together a 100% free cheat sheet on the changes in JPA 2.1. You can download it from his related excellent blog entry aptly titled JPA 2.1 - 12 Features Every Developer Should Know.
If you look around Thorben's blog you'll find that he is trying his best to craft it to be a valuable resource to the community, including a weekly Java newsletter. If you find the JPA 2.1 cheat sheet to be useful, please do spread the word and consider dropping a brief note of appreciation for Thorben's hard work.