WEDDINGS ARE OFTEN STEEPED IN EXCESS--too many bridesmaids, too much tulle, too much money spent on frosting and flowers.

It's enough to tug at one's social conscience.

DC newlyweds Billie Vaslavsky and Vincent Audric, both 27, found a way to deal with some of that guilt: Before their Paris wedding last July, they signed up with the I Do Foundation, a nonprofit that lets couples register for gifts with online stores--such as Linens 'n Things and Target--that give a percentage of purchase prices to a chosen charity.

Vaslavsky and Audric picked an education fund that supports groups like Reading Is Fundamental. They then registered through the I Do site with Amazon.com and Cooking.com. Amazon donated 4 percent and Cooking donated 6 percent of the money guests spent on presents. Vaslavsky says half their 135 guests gave gifts this way; "some of the French ones weren't as Web-savvy." The goodwill came at no extra cost for buyer or recipient, she says, and "it's so easy."

I Do also offers a Donation Registry where a couple can register for, say, five donations of $50 to their favorite cause. Guests who "buy" a donation also earn themselves a tax deduction.

This doesn't add up to major philanthropy. According to Bethany Robertson, a 30-year-old who launched the Washington-based I Do Foundation site on Valentine's Day 2002, the 500 or so couples who've signed up each raised about $100, though one reached a high of $500.

Something's better than nothing, says Ian Halpern, who with his wife, Sarah Wildman, was inspired by the I Do Foundation to make a small but, he believes, important gesture at their wedding last October.

Instead of party favors, they left a card at each guest's plate explaining that money had been donated in his or her honor to Accion International, a microlending organization, and the Israeli human-rights group B'Tselem--two charities close to the couple's hearts. They sent a few hundred dollars to each.

It's not like anyone felt deprived by the lack of Jordan almonds. "Some of our more cynical guests teased that this was an example of our 'naive idealism,' " Halpern says. "But most people were touched."

Gifts That Give Back:

www.IDoFoundation.org. Register with stores, including Linens 'n Things, Mikasa, and Target, which will give a portion of money spent on gifts to charity.

www.MarriedForGood.com. Advice on how to incorporate a range of good works into the nuptial craziness.

www.JustGive.org. Couples can create a donation wish list on this site, a San Francisco-based clearinghouse with information on more than 850,000 charities.