There is a reason such acts as the Police, Santana, Bruce Springsteen and Rush continue to fill big venues this summer: Many people who formed their core audiences in the '60s, '70s and '80s are still locked into that music.

Although those sounds were revolutionary in their heyday, many of the original listeners have gotten less adventuresome as the years have passed. They may have fewer entertainment dollars and less time available for discovering fresh music when mortgages, kids and demanding jobs are factored in.

"People have lots of options, other ways to spend their money," says Richard Gehr, who writes about music for AARP. "I know some people (middle-age and older) who are still rabidly inquisitive and curious music fans ... whereas others would rather watch HBO, read a good book, or Netflix a million movies."

For those tired of hearing "Hotel California," "Papa's Got a Brand New Bag" or "Black Magic Woman" for the 10,000th time, as well as for parents who are curious about the music their teens are listening to, the Internet is the key.

There are scores of Web sites that allow visitors to listen to and discover all types of music, for free in most cases or for a small monthly fee.

Here is a sampling of sites where baby boomers can venture beyond the classic sounds of their teens and 20s:

www.Pandora.com: This free site provides users with music that matches their tastes.

Users create "stations" by typing in the name of an artist or song title, and Pandora plays back a series of songs with similar melodies, harmony, rhythm, lyrics and instrumentation. Listeners can give a "thumbs up" or "thumbs down" rating to steer toward other material.

The site displays other visitors and the music they enjoy, and registered users can chat or post comments on message boards.

www.MeeMix.com: The brains behind this site have developed an algorithm that can predict tastes in music, CEO Gilad Shlang says.

"It doesn't matter how familiar you are with computers, the Internet, browsers," he says. "You will only have to tell us what you like and then receive a world of music based on that information."

Like Pandora, MeeMix lets users see who else is listening and sample their music.

www.Imeem.com: This socialnetworking site lets music fans click into a wide array of styles to check on which artists and songs are the most popular and most discussed.

This is a quick way to get exposed to new music in a favorite genre because the most popular songs are often new hits. This free site also has music videos and allows users to network with friends and groups, much like the popular MySpace.com.

www.MySpace.com: Speaking of this site, it's a great tool for tracking down a new artist you may have run across.

"If you hear about somebody, you go to MySpace and you find them in about two seconds," Gehr says.

Go to www.MySpace.com, search for a name under the "music" category and the material appears.

www.Last.fm: This site is helpful along the same lines as MySpace — getting information on a new artist that you saw mentioned in a magazine or heard your kids talking about.

Let's say your child is listening to Death Cab for Cutie. A search of the band at this site will indicate that Last.fm visitors think it has musical elements in common with such acts as Counting Crows, Coldplay and John Mayer.

Then view a video, listen to album samples and read a full biography of the band.

This site also provides extensive social networking, concert listings and the opportunity for musicians to post their work.

www.eMusic.com: Listeners who want to dive into the newest "indie" bands should consider paying the $10 monthly fee for this site. Customers may download 30 songs monthly at no additional cost, so those tracks wind up costing 33 cents each.

The "new on eMusic" area spotlights new releases, with details about the bands. The quirky "Dozens" feature lets experts list 12 albums linked in any manner. An online magazine is brimming with columns explaining new music in grown-up terminology.