You use the alpha (A) in the last and/or first color block to fade out the trail. Trail Renderer
Particle shaders works best together with the trail renderer.
Certainly. Others have once had the same problem, so they went and created an improved version of the trail renderer, that can fade over time. :)
It's on the wiki, take a look here:
answered May 25 '11 at 09:08 AM