okay, the conversion law kicks in for the 2010 year.
as far as i can tell, you can convert non-deductible IRA funds into a Roth IRA and when you convert, you pay tax on just the growth portion prior to conversion. for example, if you contribute $4,000 in '06, $4,000 in '07, $4,000 in '08 and $4,000 in '09, you have $16,000 of contributions prior to 2010. let's say you also earned $5,000 of growth.
in 2010, regardless of your income, you can convert that $21,000 traditional IRA into a Roth IRA. the $16,000 attributable to contributions would convert without tax. you would owe tax (presumably at ordinary rates) on the conversion of the $5,000 of gain.
you have the option of spreading the tax liability over 2 (or maybe it is 3) tax years.
of course there is no guarantee that this provision will in fact be in place in 2010. if it is, and the plan i've outlined above would work (i can't guarantee that it will - i only spent 5 minutes looking at this), it seems like that would be the best way to structure your long term investments.
i'm going to need to look into this for myself, so if anyone finds trustworthy articles on the topic, please share them.
i searched with "convert Roth 2010" to locate what i did find.
here's a link to one article that includes the following:
"Or just consider making a simple non-deductible IRA contribution each year until 2010. The maximum is $4,000 a year, or $5,000 if you're at least 50 years old. When you convert a non-deductible IRA into a Roth, you'll owe tax on the earnings."
http://finance.yahoo.com/expert/article/moneymatters/5160
here's one that seems a bit better:
"Example
Joan, age 50, has never made a traditional or Roth IRA contribution. Joan has compensation but her MAGI is $1,000,000, which makes her ineligible for a regular Roth IRA contribution. However, she is eligible to make a traditional IRA contribution. Assume that Joan makes a $5,000 nondeductible traditional IRA contribution annually for 2006 through 2010 and that her balance after the last contribution is $32,000 ($25,000 regular contributions + $7,000 earnings). In 2010, Joan converts the entire amount to a Roth IRA. Since all of her contributions were nondeductible, only the earnings portion is subject to federal income tax. She may choose to include the $7,000 conversion income on her 2010 tax return, or include $3,500 of the conversion income on both her 2011 and 2012 tax returns.
In 2011, Joan’s IRA eligibility remains the same–she cannot make a Roth IRA contribution but she can make a traditional IRA contribution. Assume that on July 8, 2011, she makes a $5,000 nondeductible traditional IRA contribution and immediately coverts the assets to her Roth IRA. Again, because Joan will not deduct the traditional IRA contribution, the converted amount is not subject to federal income tax.
Effectively, even though Joan has never been eligible to make a regular Roth IRA contribution, all of her traditional IRA contributions for tax years 2006 and later ended up in her Roth IRA due to the new conversion rule."
http://www.complianceheadquarters.com/IRA/IRA_Articles/6_30_06.html