I read that is is a renderor or something, but that’s all i could find. What exactly is it, and should I get it? Also, can someone show me the difference between a regular render and a yafray render?

Yafray is a complete render engine which in many ways is similar to the blender internal render engine. If you do or don’t use it that is completely your choice. to get yafray to work (sorry I only know the installation on windows no Linux sorry) is to simply install the latest yafray (0.0.9 at the moment) then in the render buttons window under the render button there is a drop down list with blender internal set to default, just change that to yafray. Usually you have to increase the amount of light after that. Personally I use yafray whenever I start using complex mirrors and advanced glass. Unfortunately I don’t have any very good examples of a comparison between the two but there are some nice examples of what can be achieved on www.yafray.org.

It is very similar to the blender internal render engine but the main difference is that Yafray has more realistic light rendering. Instead of the light just stopping and illuminating what ever it hits with Yafray you can make a photon light and the photons will bounce around your scene iluminating anything they come incontact with.
This is very good if you have a very high detail model that you want to look as realistic as possible Yafray will give you that last little reaslistic light boost you need.