"Tax shelter" isn't always a bad, bad thing.You can, in fact, shelter some of your income from taxes without moving a cent to some obscure European tax haven. You don't even have to be rich. Best of all, you can do it and not worry about raising tax-examiner eyebrows. All you have to do is let the Internal Revenue Service help. Yes, the U.S. tax code contains several tax shelters. But first, some linguistic clarification. Tax avoidance, or the minimization of your tax liability, is entirely acceptable, as long as you do so legally. It's tax evasion, the failure to pay or report taxes or to report them incorrectly, that will get you into big trouble with the feds. Strictly speaking, a tax shelter is any method of reducing taxable income so that your eventual tax bill is smaller. With that in mind, here are four legal, easy and IRS-approved tax shelters.