Voice Command, which uses Microsoft's own phonetic speech- recognition technology, works on devices that run the Windows Mobile 2003 operating system. It lets users dial numbers, access calendars, and launch applications by speaking commands to call a contact or asking questions such as "what's my next appointment" to view the next meeting in the calendar.
The add-on to Windows Mobile 2003 is priced at $39.95 and is available at Handango.com and PocketPC.com.