Huna is a Hawaiian word for "secret" and Max Freedom Long used it to name the techniques/religion/philosophy that he distilled from Hawaiian and other sources. There is no such things as "huna" that westerner would like to see. Huna Research counted over 2600 "schools of huna" on Hawaiian islands. If you say huna and someone else says huna, you are not necessarily talking about the exactly same thing.
Some see this as the best self-help/influence/psychology tradition of them all, and many of the "gurus" recommend it (Tad James, Style, ...)
Anyway, I almost forgot what I was about to tell you: There's a new Huna Directory
NOTE: I have placed this with a "therapy" label, with some doubts.