Over the years, brides-to-be have promised their bridesmaids dresses that they'll love, that they'll wear over and over again. But on what occasion is it really appropriate to trot out pink taffeta and a train?

So bridesmaids' gowns of late have veered away from ribbons and bows, tending toward simpler silhouettes and hip colors to more closely resemble the same kinds of elegant cocktail dresses found at women's ready-to-wear retailers. That transition sets the stage for new lines from companies such as J.Crew and Ann Taylor, both of which have launched collections within the past year of dresses and separates that cater to brides and bridesmaids. Both companies say the garments are appropriate for celebrations of all sorts, such as graduations — Ann Taylor even calls its line Celebrations.

"The wedding industry in general has gotten more fashionable. It used to be the clothes were 'ceremonial.' It used to be that everyone dressed absolutely identically. It wasn't a fashion show; it was a tradition and people wore customary clothes. All of that is still true, but the clothing is contemporary," says Millie Martini Bratten, editor in chief of Bride's magazine.

Today's brides and bridesmaids tend to be older, and the styles aimed at 28-year-olds are different from the glorified prom dresses that 20-year-olds might have looked for a generation ago. "Remember, this is a generation of people who mix casual and formal. They wear sequin tank tops with blue jeans," she says.

There is a built-in market for these dresses. According to the Conde Nast Bridal Group, the average cost of a bridesmaid dress is $138 and a typical wedding party includes five bridesmaids, for a total of $690 per wedding. It's also estimated that 23 million people will be bridesmaids or groomsmen this year, so figure half are women in need of a dress.

The outfits from J.Crew and Ann Taylor take cues from what's going on in ready-to-wear fashion, offering a range of styles and formality.

"We were already providing 'bridesmaid' dresses that weren't officially 'bridesmaid' within our regular dress line. Ann Taylor is known as a great dress resource, so we got the idea (for Celebrations) from our customers. It's a way to give our customer the choices she wants," says Adrienne Lazarus, president of Ann Taylor Stores.

What that woman will find is a core group of styles — a strapless dress with a fitted top and flared bottom is the best-seller — in a broad palette of colors. Black, navy, champagne and best-selling espresso brown are standards, while there also are seasonal colors, such as sage.

"One of the things we've found is taking silhouettes that are successful in our regular apparel line and translating them into bridesmaid dresses," says Jenna Lyons Mazeau, senior vice president of women's design at J.Crew.

The biggest change from standard bridesmaid offerings from even five years ago is the fabrics, she says. "A lot of people got caught up in fancy fabrics ... an easier-to-wear fabric gives more places for the dress to go."

J.Crew's collection is heavy on silk faille, crinkle silk and cotton cady, a double-weave Italian copy that Lyons Mazeau says takes color well. "It looks expensive but it's not too fancy. You could wear it with flip-flops, too," she says.