How should I adjust for pre-orders at the end of the year?

Our company took pre-orders for some inventory and non-inventory items before we actually had stock. We didn't have to pay for these items until 2011, but took pre-orders for them in 2010 and took payment by credit card for these items. I'm not sure how to handle cost of goods sold for these items and inventory because we received the income for these orders already, but did not have to pay our vendor for these items until 2011. Do I go ahead and record the inventory and COGS for these items in 2010 or just delay until 2011 when we actually paid our vendors? Do I go ahead and record the income on the pre-orders because we have already received the cash? Any help would be appreciated as I'm trying to wrap up our books for year end and have received conflicting answers from our CPA. Thanks!