EasyRPG is a collection of Open-Source programs for making and distributing RPGs. The EasyRPG Editor aims to be a free version of RPG Maker 2000 and 2003, and the EasyRPG Player enables games made in RPG Maker 2000 and 2003, and EasyRPG to be played on a variety of platforms (browsers, Linux, Wii, OSX, Windows etc.).
Beyond compatibility with RM2k/2k3, it has a bunch of nice features, like support for graphics with more than 256s colours.
The editor is still looking for lots of help!