Research in Motion's BlackBerry email client has become the world's most popular PDA, according to figures from Gartner.

BlackBerry sales were up 76 per cent in the first quarter of 2005, while Palm shipments fell by 26 per cent.

Research in Motion now has 20.8 per cent of the market. Palm's market share fell to 18 per cent, its lowest since 1996, and HP came in third at 17.6 per cent.

Gartner said that the growth of more usable form factors and wireless networking capability are now the keys to the market.

"PDAs with integrated wireless local area network or cellular capabilities accounted for approximately 55 per cent of all PDAs shipped in the first quarter of 2005," said Todd Kort, principal analyst at Gartner's Computing Platforms Worldwide group.

"This increase is primarily the result of the growing popularity of wireless email, with users favouring larger displays and Qwerty keyboards operated with both hands."

The survey was also good news for Microsoft, which now has the most popular mobile operating system ahead of Research in Motion and Palm. Windows CE is now on 46 per cent of all devices sold.

Europe was the main driver for growth, with quarterly sales up 83 per cent. US sales were up just five per cent, while sales in the Asian markets declined slightly.