The popularity of mobiles packed with features is set to explode as they get better and cheaper, say analysts.
Smartphones are getting smaller and easier to use
Shipments of these smartphones are expected to rise by almost 50% over the next five years, according to hi-tech market research firm In-Stat/MDR.
Smartphones cram e-mail, multimedia messaging, camera, games, video and music player, and more into one gadget.
But so far the devices have been slow to take off, hampered by their cost, size and limited battery life.
Smartphones are almost as versatile as a PC.
Devices such as the XDA II, Nokia 6600, SonyEricsson P900 and the Orange E200 smartphones set themselves apart from other mobiles by the sheer number of extras they have inside.
They offer web access, text and multimedia messaging, e-mail, calendar and gaming functions.
But according to In-Stat/MDR, only 9% of mobile phone users in the US have a smartphone.
"For a lot of mainstream users, they look at a smartphone and they say 'well, I'll just stick to my clamshell'," said InStat/MDR senior analyst Neil Strother.
"Setting up e-mail is not really convenient unless you have a corporation behind you, and battery life is still an issue," he told BBC News Online.
"And there are some security concerns, especially among IT managers."
The future, however, looks rosy for the makers of these mobiles.
The InStat/MDR report predicts that smartphone shipments will grow by 44% over the next five years. It expects that smartphones will account for some 117 million out of 833 million handsets shipped globally by 2009.
The popularity of these mobiles will be boosted by falling prices and smaller handsets, and they will be easier to use.
"We are starting to see the beginning of their mainstream adoption," said Mr Strother.
"In four years' time a lot of us with have a phone with smart abilities but we won't call them smartphones."
The report said smartphones using the Symbian operating system will dominate over the next five years, with Microsoft in second place.