According to Microsoft, the Pocket PC is "a handheld device that enables users to store and retrieve e-mail, contacts, appointments, tasks, play multimedia files, games, exchange text messages with Windows Live Messenger (MSN Messenger), browse the Web, and more." (src: microsoft buyersguide)
A Pocket PC, is abbreviated as P/PC or PPC, is a application for a
handheld-sized computer that runs a specific version of the Windows CE operating
system. It has many of the capabilities of modern desktop Personal Computers.
Currently there are thousands of applications for handhelds adhering to the
Microsoft Pocket PC specification.Some of these devices also include mobile
phone features. Microsoft compliant Pocket PCs can also be used with many other
add-ons like GPS receivers, barcode readers,and cameras.