http://www.irs.gov/pub/irs-pdf/p590.pdf
For a Roth, your earned income (with some deductions you might have taken, such as for student loan interest, added back in), must be less than:
* $160,000 if you're married filing jointly,
* $110,000 if you file as single, head of household, or married filing separately and did not live with your spouse during the year, or
* $10,000 if you lived with your spouse at any time during the tax year but decide to file separately.
And even if you're not quite at the top of these pay ranges, your Roth contribution could be limited if your modified adjusted gross income falls within these limits:
* $150,000 to $160,000 for married couples filing jointly,
* $95,000 to $110,000 for single or head-of-household taxpayers or married couples filing separately and who did not live with their spouse,
* Zero to $10,000 for married couples filing separately who lived together at any time during the tax year.
