How do I put two shaders on one object?
 

If I have a cylinder, and I want the bottom to be molten rock and then have that gradually transition to chrome at the top, how would I do that?

Use layered textures. Take a look at these tutorials:

http://www.highend3d.com/maya/tutorials/layeredtexture/
http://www.3dluvr.com/intercepto/may...of_glimpse.htm

Bye!!

Or a ramp shader.

Thanks! I'll give all these suggestions a try. That "Glimpse of the Past" tutorial looks awesome.