They are given at various Austen fanfic websites. The logins control what searches will return - that is, sites like DWG (if it had such a login) would only let you find general audience stories. If passwords get shared online, the JAFF index may get shut down until they implement some sort of access controls specifically for JAFF, which could take a long time.

I'm not sure which fanfic sites 'subscribe' to JAFF, but the two I belong to post the newest login information prominently (and I'm under the impression we're not allowed to mention even site names here - but they are very easy to find with Google). Sorry I can't just tell you, but I don't want to be the one to cause it to be shut down, since it's an excellent tool.