If one analyst is to be believed, Apple is truly making a killing on every iPhone sold -- well above competing smartphone makers like HTC, Motorola and even rival Nokia.

MacNN is reporting on the latest estimates from Bernstein Research analyst Toni Sacconaghi which claims that Apple is enjoying a healthy 57.8 percent gross profit margin on the iPhone. For comparison, Blackberry maker Research in Motion only keeps 42.6 percent of its sales revenue, and Apple is dwarfing the gross profit of other longtime smartphone makers such as HTC, Motorola and patent rival Nokia as well.

Sacconaghi believes that the iPhone will account for between 45 and 50 percent of Apple’s annual revenue come 2011, up from 30 percent in 2009.

Those numbers contradict the overall Wall Street consensus, which seems to feel that Apple’s gross margins will fall 10 points in the next two years. But Sacconaghi argues that those estimates are predicated on a $100 drop in average iPhone sale prices, a 700 basis point drop in iPhone gross margins or even “significant damage” to the rest of Apple’s business.

Even in a rocky worldwide economy, the iPhone has bucked the trend -- customers are still willing to pay the high price of the device and accompanying data plan at the same time that the competition continues to drop their prices on devices such as Palm’s Pre and Motorola’s Droid.

“We would argue that the reason for such margin disparity is that Apple’s products have unique software and user experiences, which differentiates them from commodity hardware offerings,” Sacconaghi explains.

Sacconaghi also suggests that there won’t be an iPhone from Verizon until “the middle of next year” at the earliest. The analyst predicts that T-Mobile’s U.S. division is more likely to get the device before Verizon.

On the subject of the forthcoming iPad, the gross margin is estimated to be more like 30 to 32 percent -- contradicting the 50 percent claimed in an early iSuppli breakdown.