My accountant advised that I reimburse myself for insurance premiums paid in 2008, and that it would have to be added as income on my w2. Where does this need to be added?

You reimburse yourself for Health Insurance costs, why? That is kind of odd do you own your own business. If so are your health insurance charges deducted from your weekly paycheck? That would mean you deducted them from your "Taxable Income" and therefore yes you need to add anything that was deducted back into your personal income. How did you reimburse yourself separate checks like an expense report for example? How you got the money back I believe would determine how you report it.

The easiest way I can think of is to have your W-2 re-issued without the deduction for your health insurance from your reportable income. Would be difficult for most people but if you are in a position to be reimbursed for your health insurance (owner?) you should be able to do it.