The Internal Revenue Service unveiled its annual listing of tax scams Monday that it labeled the "Dirty Dozen." The 2004 list includes several new tricks that either manipulate laws governing charitable groups, abuse credit counseling services, or rely on refuted arguments to claim tax exemptions, according to the IRS. "The Dirty Dozen is a reminder that tax scams can take many forms," said Mark W. Everson, IRS commissioner. "Don't be fooled by false promises peddled by scam artists. They'll take your money and leave you with a hefty tax bill."