Airlines are keen to sign you up for their sale email alerts, but that means scanning them for routes and dates you actually are interested in, and often leads to inbox overload. GetFlight lets you specify routes you're interested in and sends you an email if a sale fare appears on that route.The service monitors the four major domestic airlines (Qantas, Virgin, Jetstar and Tiger) plus a bunch of international carriers. The site's founders say it covers 100 cities and 30 countries. You can also specify a price and search for any fares under that price, and exclude specific airlines.
If you find a flight you fancy, it's linked direct to the relevant airline site -- there's no extra booking fee, which is our usual objection to many flight search sites. All up, seems like a handy service.