The Apple iPhone has been toppled from its No. 1 spot by the BlackBerry curve in the Q1 2009, putting an end to the phenomenal run which started since its launch.

However, this doesn’t mean an adieu to the market supremacy of iPhone, said Ross Rubin, an analyst for researchers The NPD Group.

A survey conducted by NPD for the top-selling smartphones between January 1 and March 31, were in the order of the BlackBerry Curve, the Apple iPhone 3G, the BlackBerry Storm, the BlackBerry Pearl (not including the Pearl Flip) and the T-Mobile G1 with the Android operating system.

Referring to the strong performance of the Blackberry Curve, Mr. Rubin said that the handset was a hit due to two reasons- Verizon’s ‘Buy one, get one free’ deal for the Blackberry and the availability of the handsets via four major carriers, in contrast to iPhone which is only there on AT&T.

This could spell a successful time ahead for the yet-to-be launched Palm Pre, which is touted as the biggest challenger for iPhone.

“When a carrier supports a device, it does well,” Mr. Rubin said.

Besides, T-Mobile G1’s entry into the top five phones is also an interesting development, indicating the growth of the smartphone category regardless of the typically higher cost of their calling plans.

“We see smartphones continue to gain share in the overall handset category,” said Mr. Rubin.

For the times to come, iPhone may regain its position with BlackBerry having already ended its promotion.