No. You do not need to do anything to receive the $250 rebate – aside from reaching the 2010 Doughnut Hole.
Your 2010 Medicare Part D plan will notify Medicare when you reach the Coverage Gap portion of your prescription drug coverage.
Medicare will then automatically send you the $250 rebate check within 45 day of your having reached the Coverage Gap.
You do NOT need to complete any forms.
CAUTION: Anyone who asks you to complete a form to receive your rebate check is probably part of a SCAM.
Please report these people/organizations to Medicare at 1-800-633-4227.