Free software projects have the irritating habit of choosing names that fail to reflect what the software does. A case in point is KBarcode. Although KBarcode does generate the barcodes you would expect from its name, for most people, it is probably far more useful as a label and business card editor. Anyone looking for these functions could easily overlook it because of the name -- and that would be unfortunate because, even with some awkward interface designs, KBarcode still compares favorably to similar programs.
KBarcode is a standard program in most distributions' KDE offerings. It opens with a configuration wizard (also available from Settings -> Start Configuration Wizard) whose main purpose is create an SQL database for use with the program. KBarcode supports MySQL, PostgreSQL, and SQLite, but not common data sources such as Mozilla address books or other KDE programs such as Kontact, let alone GNOME's Evolution.