Strategy Analytics, in Boston, estimates that BlackBerrys handle 59 percent of corporate wireless e-mail traffic.

Apple has a 19 per cent share and Samsung has 18 per cent, according to analysts Strategy Analytics.

However, Strategy Analytics say that Samsung's share is growing more quickly than Apple's, suggesting that the lead could change hands again soon.

According to Strategy Analytics, smartphone sales are up 76 percent for the second quarter, up to a record 110 million units.

Strategy Analytics, a market and consulting firm in Boston, reported that domestic sales of custom ring tones were $128.6 million last year.

Apple shipped 14.1 million handsets during the most recent financial quarter, up 91 per cent on the same quarter last year, according to analysts at Strategy Analytics.

In the third quarter of 2000, Motorola's share of sales fell 2.3 percentage points, to 13.3 percent, according to a study by Strategy Analytics, a consulting firm.

Strategy Analytics predicts that 280,000 plasma screen TV's will be sold this year in the United States, up from the 150,000 sold last year.

The iPad still dominates tablet computing market, however, accounting for 67 per cent of sales in the third quarter, according to Strategy Analytics.