http://www.youtube.com/watch?v=3Sfw_PRRlhU
Interesting what you can do with these things.
I've built an automatic smelter, very easy with 3 hoppers, 2 chests and a furnace.
I can smelt a lot of stuff while I mine!
Yeah, I built one of those four high sorters, lower half is blocks, repeaters, torches, etc, and upper section is three hoppers. it works rather well if you can keep your system from glitching out. mine was being finicky with eggs, and causing the filter items to completely exit the system so the sorting broke.