Anything from the Indian culture would be a good cultural reference - after all, that is where the rakshasa originates. Some quick links include:
http://en.wikipedia.org/wiki/Rakshasa
http://members.toast.net/stygian/rk/main/green/intro/about.html
Specifically, look at <a href="http://en.wikipedia.org/wiki/Vibhishana">Vibhishana</a>, who was a good rakshasa. Interesting stuff.
Overall, the concept of a rakshasa monk is a good one, especially if he/she/it follows the path of Vibhishana.
I am looking for some info about Rakshasa culture.
How do they chose their names?
How do they organize thei community (tibes, clans, families)?
Are all Rakshasa spellcasters or does their society know fighters & monks?
I would like to make a lawful-neutral Rakshasa monk, this is why I ask.
Unfortunatelly Rakshsa seem to be mosty lawful-evil spellcasters.
I haven't actually seen that much written about them. I know they play a big role in the Eberron campaign setting as members of the Lords of Dust. They also preside over the Demon Wastes as that is where their HQ are located. You can find a bit more about them in the Eberron CS hardback. They also come in several different varieties. There is the standard Rakshasa as it appears in the Monster Manual. There is another variety called the Zakya which are written up in the Eberron rulebook. I think they are more martial in focus than the regular Rakshasa. And lastly two other varieties appear in the Monster Manual III, the Akchazar and the Naztharune. I see them as Necromancers and rogues/assassins respectively. I don't see why you couldn't use them as templates to make a monk. Rakshasa are as varied as humans imo.