The Internal Revenue Service has issued its 2010 “dirty dozen” list of tax scams, including schemes involving return preparer fraud, hiding income offshore, and phishing.“Taxpayers should be wary of anyone peddling scams that seem too good to be true,” IRS Commissioner Doug Shulman said. “The IRS fights fraud by pursuing taxpayers who hide income abroad and by ensuring taxpayers get competent, ethical service from qualified professionals at home in the U.S.”