Frequent-flier programs are always changing - sometimes for better...sometimes for worse.

The newest opportunities and how to take advantage of them...

The Internet offers a wide range of special offers. Frequent fliers who aren't already Internet-savvy might find this is a good time to learn. Examples...

- Continental and Northwest have begun to advertise last-minute weekend travel specials for frequent-flier program members - but only over the Internet.

- Every week, Continental posts a new special frequent-flier offer. Recently I noticed a weekend flight from Colorado Springs to New York requiring just 12,500 miles - half the miles a ticket would normally cost.

- Sometimes airlines' special Internet prices are as low as 7,500 miles, instead of the customary 25,000 miles. Web-Flyer (www.webflyer.com) posts all available airline deals.

- Internet deals are frequently valid only for an upcoming weekend, so you can't really plan ahead. But if you're looking for something to do over the weekend, they offer great opportunities.

Call the airlines or your travel agent for the name of Web sites that correspond to the airlines flying to your desired destination.

- Growing partnerships mean you may be better off using the miles on the ground. Travelers increasingly are finding that free tickets are not the best use of their miles.

Reasons: Key travel days often are blacked out ... securing a free seat often requires advance notice ... you often have to fork over 40,000 miles since most of the 25,000-mile seats are taken in advance.

Better: Consider using frequent-flier miles to cut the cost of renting a car or staying at a hotel. Many airlines have partnerships with these companies. Call your hotel or car-rental company for information.

Example: American Airlines' plan is the best from a total-trip standpoint, as its miles can be redeemed at both major hotel chains and car-rental firms.

- The number of last-minute frequent-flyer seats is on the rise. Many airlines are becoming more willing to offer seats on selected flights to frequent-flier travelers that were originally designated for paying customers.

While it's still best to reserve a frequent-flier ticket three or four months in advance, you have a shot at getting one when you are told none is available by calling the airline every two weeks.

Increasingly, airlines are releasing extra seats to frequent fliers seven to 10 days prior to flights. By that time, the airline will have a pretty good idea if there will be unsold tickets. This creates great opportunities for frequent fliers who are willing to wait until the last minute.

- Leave yourself enough time to check in.

United Airlines recently enacted a rule that requires frequent-flier passengers to check in at the departure gate at least 20 minutes prior to their flights - and at least 30 minutes for international flights. Other airlines are expected to follow. This new rule replaces the old 10 minute requirement.

Frequent-flier award redeemers who lose their seats will have to stand by for other open seats on later flights - with no guarantee when or if seats will be available.