Powerline Ethernet Adapters:  Current (Sept 06) situation appears that residential powerline standard is around 14 mbps, but that different vendors extend it up to 200 mbps max.  Carrying HD signals at 28 mbps is an important threshold, with conventional digital video of 20 mbps also important.  Netgear does well, as does Zyxel.  Both are $100-120 per adaptor.  Linksys has older models at 14 mbps only selling for $65 per adaptor or used down to $30.  Both Linksys and Zyxel have adaptors for USB at about the same price as Ethernet.
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