The limits for deducting a 2011 IRA contribution were recently set. Unlike the relatively straightforward guidelines for 2011 Roth IRA contribution eligibility, deductibility for 2011 IRA contributions is based on modified adjusted gross income (MAGI), marital status, as well as your and your spouse's ability to contribute to a workplace retirement plan (e.g., 401(k), 403(b)).
Even if your regular IRA contribution is not deductible, the growth in the account continues tax-deferred; it is only the upfront contribution which might not be deductible. If so, note when you begin to take your money out from your IRA during retirement, a small percentage will not be taxed. So look at this non-deductibility as a small bit of bad news today with a small bit of good news in the future.
One last thought: if you can't make a deductible IRA contribution and wish to save more for retirement, consider increasing your 401(k) plan contribution (no income limits on deductibility) or, if you are eligible, a contribution to a Roth IRA instead. While a Roth IRA won't provide you with an upfront tax deduction, its earnings will grow tax-free.