In the wake of the terrorist attacks, Americans are opening hearts and wallets. The Web offers clearinghouse sites that help you evaluate charities.Helping.org: The best of the bunch. Data on thousands of charities, with links to make donations. A search engine matches you with volunteer opportunities near your home. CLICK!Give.org: Run by the Better Business Bureau, it offers some of the same info as Helping.org--but uses graphics to show how much of your donation will be spent on administration and fundraising. CLICK!Libertyunites.org: Site was created by six tech companies after the terrorist attacks. It channels aid mostly to New York agencies, especially for post-WTC relief. CLICK!