October 15th, 2012 is the deadline to recharacterize Roth IRA conversions that were done in 2011.
Roth conversions are great because you have until this October 15th of the year following the year of the conversion to change your mind for whatever reason. Perhaps the account went down in value or you don't have the money to pay the tax, no problem, you get a do-over.
If the value of the Roth IRA has declined after a conversion it might pay to recharacterize. Let's look at an example. Suppose you converted $100,000 on 1/1/2011 and you are in the 25% tax bracket. The tax due for the conversion would be $25,000. Now suppose the account dropped to $50,000; the tax of $25,000 relative to the current account value is now 50%, not 25%. Recharacterizing would allow you to move the $50,000 back to the IRA and you get your tax money back. And once you wait the prescribed period (the later of the following tax year or 30 days) you can re-convert the same funds. In my example, now you only have $50,000 to convert and at 25% the tax is only $12,500. So you still have only $50,000 in the Roth IRA however the cost to get it there was $12,500 less! A great deal. Roth conversions allow you to "bet on the horse after the race is over."
Keep in mind that this is only for 2011 conversions. Some people converted in 2010 and took the 2-year deal which allowed them to spread the inclusion of the income on the conversion, half in 2011 and half in 2012. So for these years you are including income from a conversion that occurred in 2010. If you are wondering if you can recharacterize either of those amounts, the answer was no because the conversion was in 2010 and that deadline was 10/15/2011.
Remember too that the current tax rates are set to expire on 12/31/2012 and unless congress acts to extend the Bush tax cuts, the tax rates are going up and there will be the additional 3.8% surtax on net investment income. So if you recharacterize and plan to reconvert in 2013, be aware of the possibility of higher taxes and depending upon the situation, you may be better off not recharacterizing.
See September's IRA Update for more details regarding Roth Conversions and Recharacterizations.