Kuju Entertainment has released its Mapster software as open source software to aid developers in the creation of Game Boy Advance titles. Mapster allows developers to easily build arbitrary sized, tile-based images for use with the Game Boy Advance. These images can be used to quickly create a variety of game environments, from traditional top-down scollers to mode 7-style racing or shooting games.
Mapster supports different map building techniques including simple tile-by-tile painting, tile smoothing and a simple map renderer that exports to TGA files for further processing. There is also support for creating large multi-tile brushes to paint with, as well as transparency and brush previewing on Windows 2000/XP.
Mapster is available for free as a download.