"sleep" mode and other questions

is there any way to make arduino sleep if conditions are met. I think the atmega8 supports this, but I’m not sure if it’s something you can program…

also, I wanted to say that I am happy that you guys are updating and pushing forward on a regular basis. I am slightly disappointed in “wiring” as the software is getting stale, emails go unanswered, and the forum is fairly quiet. keep up the good work.