please, never ever mention shiva and lua again tongue
To be honest, I think that ShiVa is pretty good in terms of speed, browser and iPhone support. But the coding is just a pain in the ass, they should redesign that whole system in my opinion, as it could be a great engine then. And I think it still doesn´t allow custom shaders...

Lite-C Tut. 1 Lite-C Tut. 2 Lite-C Tut. 3 (en)
Shader Tutorial (ger)

http://www.slindev.com