(FORTUNE Magazine) – It is time to rethink the notion that fast-track law school students are motivated by greed alone. The National Association of Students Against Homelessness (Nasah) has raised some $38,000 for the needy by touching a philanthropic nerve in the law firms that want to hire them. The idea was born last year when Harvard law student Joseph Anderson was working as a summer associate with a New York City law firm. A homeless man dropped to his knees and begged for food money as Anderson headed home after a meal in the SoHo district. Anderson was struck by the disparity between the frills lavished on him by law firms that had interviewed him and the poverty of the homeless. Says he: ''I saw the excess as a resource that could be channeled to other means.'' Other law students had similar experiences. So they cooked up a plan whereby students on the interview circuit may opt to stay in modest hotels and eat in less expensive restaurants. The interviewing firms donate the difference in costs to shelters for the homeless. When students fly to interviews, they book through a travel agency that turns over 50% of the commission to the needy. More than 600 of Harvard law school's 1,100 second- and third-year students who are now job hunting take part in the program. Says student Lisa Ferrell, 26, a director of the program: ''There's a massive response that proves we care.'' Ferrell says she has been saving $30 a night on hotels while on the road interviewing and $45 a lunch for her and prospective employers. With four interviews so far, that comes to $300. Students at 13 other law schools, from Yale to UCLA, have set up Nasah chapters. And about 150 law firms, including New York City's Debevoise & Plimpton and Boston's Bingham Dana & Gould, are participating.