Dual Core now has 2 Ethernet Ports - Can I use both simultaneously

Just wondering, I am not to savvy about networking so need a little help. I noticed the new Dual cores have dual ethernet ports. Can I use both simultaneously. This is my situation.... I have a G5 and an iMac G3, with Tiger I can set it up so that I can send midi over a network or "ethernet (computer to computer)", with the help of another software program I found I can also send Audio over a network. I have already tried it between my imac and my current G5 and it works great....So the question is if I were to by say a Dual core G5 and maybe 2 of the newer Dual core mini's would I be able to simultaneously send info to both minis - one mini connected to ethernet port 1 and the other mini connected to ethernet port 2. Will it affect the bandwidth (such as when you have more than one firewire device hooked up to a firewire port? I am not sure how the ethernet thing works, but If I can send info to both minis at the same time that would be cool.

Thanks

G5 2.0 Ghz