Welcome! I'm sure that you'll find lots of info here.
Well, the deal with the speakers is that a standard 2 or 3-way
speaker is an 8-ohm
impedance. Two speakers wired in series (connect
power amp to first one, and
power out from the first one to the second) is a 4
ohm load. So no, you can't get 4
ohm power on 8
ohm speakers. I'm not a crazy
speaker theory person, but I can tell you this: a
speaker can only be driven at its specified
impedance, because it will not be able to provide the lower
impedance for the amp.
I'd really recommend that you
pick up a copy of "Audio Made Easy (Or how to be a Sound Engineer without really trying)" by Ira White from Amazon.com. It's quite possibly the easiest read for beginner audio folks, and is a textbook for many beginner sound courses at college that I've visited. It'll explain a lot of stuff.
But you are always welcome to ask questions here.
EDIT: Gah...Twice in a row...it's PARALLEL, not SERIES for those impedances.