LTO (Linear Tape Open) is a popular open format for magnetic tape data storage. Barcoded labels can be used to link cartridges with backup software, but they typically retail at high prices.
Jerome Alet has created an easy to use web service for generating them. His TapeLabels website makes heavy use of the ReportLab ToolKit's great support for barcodes, creating sheets of labels which can be directly printed onto a number of different self adhesive label sizes. Because the site uses ReportLab's support for PDF forms, the resulting files are very small and they generate at very high speed.
Best of all : it's free!
Try it here: http://tapelabels.librelogiciel.com