It's calculated in for this year, or is it retroactive to 2008?
If they owe us money for 2008, will they pay interest on the IOU?
Can we have our employers stop taking out CA state tax until the IOU is fulfilled?
The estimates in the Assy Report show zero for the current fiscal year and a $3.3 billion dollar increase next year (at 5% surtax).
Some of the other shenanigans do apply to the current year (sales tax, VLF fee, etc).
See link above.
If you mean that the tax rates have increased by 5% (eg., the 9.3% tax rate is now 9.765%) then the answer is yes. If you mean the tax rate is 5% higher than it was (eg., the 9.3% tax rate is now 14.3%) the answer is no.
It's calculated in for this year, or is it retroactive to 2008?
It's a "one-time" surcharge on 2009 taxes only. But we all know what happens with "temporary" taxes, don't we?
If they owe us money for 2008, will they pay interest on the IOU?
No.
Can we have our employers stop taking out CA state tax until the IOU is fulfilled?
Sort of. The strategy I'm using is that if the state owes me a refund for 2008, I'm going to apply it towards my 2009 taxes, rather than getting a refund (IOU). Then I'm going to lower my withhold on my paycheck until I've recovered what I was owed in a refund. Once I've "broken even", I'll change the withhold back to where I started.