By Becky Waring

If your travel budget is being strained by steadily rising airfares and an accompanying dearth of frequent flyer seats, you're not alone. Thanks to major reductions in flights and overall capacity, as well as increased competition from cash-short travelers, those coveted free award seats are harder than ever to come by.

But what you may not know is that frequent flyer seat availability comes and goes. Passengers who book seats far in advance may change their plans, or if a flight is not filling up, airlines may increase the award seat quota as it gets closer to the departure date. So if you only check availability once, you may miss your opportunity to book that seat.

Similarly, airfares have significant seasonal fare variations, and if you book at the wrong time, you may pay more than you need to.

That's where new automated flight search services like Yapta and Farecast come in. Both are completely free to users. Simply tell Yapta what flights you are interested in (enter as many as you like), and it will send you regular updates about frequent flyer seat availability, the lowest airfares or both. And if you've already bought your ticket, it will notify you when and if the fare drops lower so you can get a refund on the difference! (Any rebooking fees are taken into account.)

Yapta is a relatively new site, but it already tracks fares on most major airlines, for both domestic and international flights. For frequent flyer seats, it asks for your membership numbers, and then logs onto the airlines' sites regularly to check availability. So far, award seat tracking is supported for Alaska, Continental, Delta, United and U.S. Airways.

Farecast (which was recently purchased by Microsoft) takes a different angle on finding low airfares and hotel rates: scientific prediction. Search for a flight, and it will tell you if it thinks the lowest airfares to your destination will rise or fall over the next 7 days, helping you decide when to make the purchase. For hotel stays (in 30 cities so far), Farecast tells you whether a rate for a particular hotel is a good deal, based on comparisons between the current rate and past rates at the same hotel.

If you still can't find a good fare or award flight on your favorite airline, consider sites like Priceline and Hotwire, where you can bid on airline seats and hotel rooms. While you won't know who the provider is up front, in times of lower demand you can often snag great deals this way.

Whatever strategies you use to find the best fares, don't forget to go back to book them at the airline or hotel site, rather than a general travel provider like Expedia or Orbitz. You'll save the add-on fees and be able to do things like select seats, apply for upgrades and track your mileage easily. Bon voyage!