Worldwide sales of smartphones were up 74% year-on-year in the second quarter of 2011, according to market research firm Gartner.

Smartphone sales accounted for 25% of overall sales in the second quarter of 2011, up from 17% the previous year.

Google and Apple are the winners in the smartphone ecosystem, said Gartner.

The combined share of iOS and Android in the smartphone operating system (OS) market doubled to nearly 62% in 2Q 2011, up from just over 31% in the corresponding period of 2010.

Gartner principal research analyst Roberta Cozza said smartphone sales continued to rise at the expense of feature phones.

Cozza said: "Consumers in mature markets are choosing entry-level and midrange Android smartphones over feature phones, partly due to carriers’ and manufacturers’ promotions."

However, replacement sales in Western Europe showed signs of fatigue as smartphone sales declined quarter-on-quarter, said Gartner.

In smartphones, Nokia’s sales into the channel in the second quarter of 2011 were low.

"The sales efforts of the channel, combined with Nokia’s greater concentration in retail and distributors’ sales, saw Nokia destock more than 9 million units overall and 5 million smartphones, helping it hold on to its position as the leading smartphone manufacturer by volume," said Cozza. "However, we will not see a repeat of this performance in the third quarter of 2011, as Nokia’s channel is pretty lean."

Worldwide sales of mobile devices to end users totaled 428.7 million units in the second quarter of 2011, a 16.5% increase from the second quarter of 2010, according to Gartner.

Samsung achieved strong growth in sales of mobile devices. Apple continued to exceed expectations, and is the seventh-largest mobile phone vendor and the third-largest smartphone vendor, said Gartner.

Research In Motion’s (RIM’s) share of the smartphone market declined to 12% in the second quarter of 2011, from 19% a year ago. Also, the company lost its No. 5 position in the worldwide ranking of mobile device vendors to ZTE.

Gartner expects sales of mobile devices to grow around 12% in 2011.

Nathan Marke, CTO at 2e2, said the increasing number of mobile devices being used at work create additional headaches for businesses.

"The immediate requirement is for basic smartphone and tablet control services, such as data encryption and remote device lock and wipe. Interestingly, we are seeing a significant preference for SaaS rather than self-managed on-premise solutions," he said.

"As enterprises wake up to the threat represented by unstructured corporate data being stored and accessed on mobile devices, we are likely to see more of them wanting the ability to administer consistent policies across their fixed and mobile estates. This will require enterprises having a coherent strategy when it comes to ID management, access, anti-virus, anti-malware, anti-spyware, data backup and so on," Marke added.