World wide PDA shipments continue to grow, with Research In Motion's (NASDAQ: RIMM) Blackberry device leading the way, according to a new report.

The market for personal digital assistants (PDAs) rose 18.4 percent in 2006, over the previous year, with record shipments of 17.7 million units sold worldwide, according to research firm Gartner. The firm said that mobile data access and wireless email was the driving factor of the year's phenomenal growth.

60 percent of all PDAs shipped in 2006 offered cellular connectivity, up from 47 percent in 2005, said Todd Kort, principal analyst in Gartner's Computing Platforms Worldwide group.

Of the PDA vendors, Research in Motion led with an estimated 19.8 percent market share, selling 3.5 million units in 2006. Last year, the firm had 21.3 percent market share. Gartner says the firm is experiencing slower growth for the firm, however, as the device maker has been rapidly shifting towards Smartphones following the September launch of its BlackBerry Pearl.

RIM competitor Palm saw its PDA shipments decline 29 percent in 2006 as the company continued to focus on the smartphone market with its Treo product line.

Despite strong sales from device manufacturers in 2006, the real winner may be the software companies that power the devices.

RIM utilizes its own operating system for its PDAs and smartphones, while some Palm devices use the in-house designed PalmOS. A majority of other manufacturers use Microsoft Windows Mobile OS, giving the Redmond Wash.-based company the lion's-share of mobile software share.

Windows Mobile achieved its highest sales ever with PDA OS shipments exceeding 3.5 million compared with 2.2 million units in the fourth quarter of 2005. This strong quarter helped Windows Mobile to solidify its stronghold on the market with 56.1 percent market share for the full year

Gartner defines a PDA as a data-centric handheld computer weighing less than 1 pound that is primarily designed for use with both hands. It can use an open-market OS and supports third party applications.

Smartphones offer all the attributes of a PDA, except that smartphones are voice-centric with data access as a secondary capability, and are designed for primarily one-handed operation.

Shares of RIMM were lower in Tuesday mid-day trading on the Nasdaq Stock Exchange, losing 87 cents, or 0.64 percent, to $135.98.