The mineral fair I'm going to(and planning to buy a meteorite) is tomorrow, so I'll have to pack in a lot on this post.
part 1 is here http://odysseypod.blogspot.com/2011/05/meteorites-part-1-basic-info.html
part 2 here http://odysseypod.blogspot.com/2011/05/meteorites-part-2-rock-or-metal-or-both.html
Stony meteorites with tiny mineral grains, called chondrules(and that's the point where I started getting geeky- even my spellchecker draws a red line on the word. Hey, I've double checked the spelling!) inside are called chondrites, and most of the stony meteorites are these.
These chondrites were actually made when the solar system was born.
The chondrules, the grains are usually made of olivine and pyroxene, but I don't care about that stuff.
Chondrites haven't changed since the solar system was made, but another type of stony meteorites, called echondrites (doesn't have the grains like a chondrite), iron meteorites and stony-iron meteorites are the remains of a planetesimal (small planets) that broke apart when they bumped into each other.