Want to walk for a good cause but find yourself strapped for time or physically incapable? Welcome to the “virtual walk” where you can raise money for charity without ever stepping out the front door.

Some 1,500 women began a 31-city virtual walk across the United States on Monday to benefit breast cancer courtesy of a computer, an avatar and a $3 donation.

Participants included home design guru Martha Stewart, British actress Lynn Redgrave, actress Mena Suvari and Jorja Fox of the “CSI” television show in what organizers said was the world’s first interactive virtual walk.

The “Gal to Gal Virtual Walk” ( www.galtogalwalk.org) is the brainchild of Oregon entrepreneur Jeanne Fitzmaurice who created a foundation in 2005 to raise money for patients in the final stage of breast cancer after two close friends died of the disease.

Supporters design their own Gal avatar, or Internet representation, for a $3 donation, add clothes and accessories and a personal story and then watch themselves walk from Boston to San Francisco against a changing daily landscape.

Fitzmaurice said the idea was to help busy women, no matter what their physical condition, lend their help in a fun, creative way during October’s Breast Cancer Awareness Month. She hopes that one million walkers will sign up.

“You can give thousands of women dignity and comfort when they need it most from the luxury of your own home … We don’t care if you are in your sweatpants, just do it,” said model-actress Molly Sims, who is one of those taking part.