Actually interrupt*() functions are not implemented yet.
Sorry for that guys, but we didn't had the time to implement it on time for launch, this is one of our high priority for the next 1.5.1, that will be released ASAP.
Graynomad's description of interrupt capabilities is very accurate, but the current Arduino API (that we are going to implement) cannot be used to exploit all of them. An API update should be taken into account, but this is food for discussion on the developer's list on the coming weeks, for now we must stick to the current 1.0 API.
C