Roth conversion in 2010 has two new angles

First, you can convert to a Roth IRA at any taxable income level. Before, your AGI had to be below $100,000. Now it can be anything.

Second, you can split your conversion tax over the next two tax years. Here's an example of how that will work:

Step 1: Convert $200,000 of IRA to Roth IRA in 2010.

Step 2: Pay tax on half ($100,000) of the conversion in tax year 2011. You'll owe the tax by April 15, 2012, using 2011 tax rates.

Step 3: Pay the other half of the conversion tax in tax year 2012. You'll owe the tax by April 15, 2013 using 2012 tax rates.

Now it is true that if tax rates are increased in 2011 or 2012, you may owe more tax on your conversion in those years than if you just went ahead and paid all the tax in 2010 tax year. But remember, you'll have time for your Roth account to grow tax-free while you are waiting to pay the tax.

So, if tax rates rise a little, you are probably better off waiting to pay the tax. But if they rise dramatically, you are better off just paying it right away.