Wiring in series or parallel

Wiring in series, take your speaker wire and connect the + side to the red speaker terminal of one speaker, the - to the black terminal on the other speaker. split one of the wires in half, or just use one side, but connect the - of your first speaker to the + on your other speaker. Whatever the ohms are for your speakers, they will now double. Example, one 4 ohm speaker in series with another 4 ohm speaker now presents an 8 ohm load.
Wiring in parallel, connect both +'s (red) together, both -'s (black) together. Now your ohms will be cut in half. Example, one 4 ohm speaker wired in parallel with another 4 ohm speaker now presents a 2 ohm load.
Simple, huh? Good luck!

By the way, if you go the series route, you can lower the overall impedence by slapping a resistor across the + and - outputs (make the resistor equal to two times the impedence of your speakers -- e.g., your speakers are 8 ohms so in series they are 16 ohms so you would need a 16 ohm resistor in in parallel across the speakers so the total load drops back to 8 ohms).

See this recent thread for some good suggestions on raising or lowering the impedences and the devices you can use:

http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1080863019&read&h12&zzlArj&&#rest

Good responses. Ozfly, I had forgotten the thread you listed. Very informative.