Apple now tops other handset makers in terms of revenue, according to new estimates.

With big iPhone sales during the quarter, Apple passed mobile giant Nokia in revenue, making it the world's largest handset vendor based on that metric, according to Boston-based Strategy Analytics.

"We estimate Apple's wholesale revenues for its iPhone handset division stood at $11.9 billion in the first quarter of 2011," said Strategy Analytics' Senior Analyst Alex Spektor in a statement, referring to U.S. dollars. "Apple overtook Nokia for the first time, which recorded a lower $9.4 billion of wholesale handset revenues."

Apple sold 18.65 million iPhones in its most recent fiscal quarter, up from the 16.24 million in the previous quarter. Perhaps more impressive is that the iPhone made up a little more than half of the company's $24.67 billion in revenue from the entire quarter.

Nokia, which released its earnings earlier today, actually outproduced Apple in terms of raw handset numbers, shipping 108.5 million handsets, with 24.2 million of those being smartphones. Strategy Analytics notes that the revenue gap between to two centers on the average selling price. While Nokia's hovers at $87 per phone, the firm estimates Apple's at $638 (this is before carrier subsidies). Apple itself does not disclose how much it sells the iPhone for to carriers.

Despite the revenue lead, the firm estimates Apple is still destined to lose ground to Google's Android next year, as well as face increased competition from Nokia, which today announced that it has formally entered into its strategic partnership with Microsoft. This is the deal that will have the two companies working together to create Nokia hardware that runs Microsoft's Windows Phone mobile operating system.

"Apple's proprietary ecosystem of hardware, software and services has proven wildly popular and hugely profitable. However, rivals are chasing hard, particularly the Android vendor community, whose global installed base of smartphones we estimate will exceed that of Apple's by the end of 2011," said Neil Mawston, Strategy Analytics' director in a statement. "Nokia is also investing heavily with Microsoft and Apple will be a key target for them next year."

Nokia has pledged to have handsets running the Windows Phone OS in 2012, though several could be released before the end of this year. Apple is rumored to be planning its next iPhone release for September.