If you have a Pocket PC running the Pocket PC 2002 operating system, you may be able to upgrade your device to the Pocket PC / Windows Mobile 2003 OS if an upgrade was released for your handheld. The problem is that these upgrades are now difficult to find.
Enter eBay.com. eBay offers auctions of many different hard-to-find software titles, including Pocket PC / Windows Mobile upgrades. Below are listings of Pocket PC / Windows Mobile 2003 upgrades available for auction. Check the auction listings for device compatibility.