Bi-wiring simply means that your base drivers have their own set of wire running to them and the tweeter and the mid range have their own set of wire, there is alot of debat on wether or not this actualy does anything for you seeing as the power is still being drawn from the same source.
I personally have my speakers bi-wired. Onecall has cheap Audioquest bi-wire cable (ducking my head). Or you can simply jump the two connections together on the back of the speaker as suggested by somone else. Its entirely up to you.
If you search the forums there is a article some where around here about bi-wiring.
I hope this info helps you understand a bit more about what those connections are on the back of your speaker and why they are there.