There is a library for JodaTime that provides Hibernate persistence. Recently I started looking at Joda-Money and started to see how that can be persisted using hibernate and I
Joda-Money's very new, so it's no surprise that noone's provided a Hibernate mapping for it yet.
However, writing custom Hibernate type adapters is pretty straightforward. If you look at the source for the JodaTime adapters, you'll see they're really simple. See the docs for how to write your own.