Since 2011 aren't due out until late 2009, you're not going to have to look any time soon.
Typically rates come out about 18-24 months before the sailing dates. If you are using a TA, why not just ask them to call you when the rates are available? Otherwise, I wouldn't even start looking until late 2010 for 2012 rates. About November 2010 you'll want to start checking regularly here or on the DCL site!
DCL typically releases dates/rates in the Fall. Supposedly, the 2011 dates will be released sometime this November, so I would guess that 2012 won't come out until the Fall of next year.
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