Hi,
I ported and edited, improved (majorly) a pretty simple GLSL raycaster. You'll find the source here: https://code.google.com/p/lwjgl-glsl-raycaster/
Be free to do as you please with it. I don't know what the original's license was, so I made mine the restrictive GPLv3. If you'd like, I can change that, just have to find the original source and replace/rename some things (the code is not much recognizable with the original but still).
Video: http://www.youtube.com/watch?v=MNVX_PjqEpc (recorded with VLC, crappy)
Have fun with it!
Greetings,
Kajos
P.s. Mods, can you place this is the appropriate section if applicable?