If your community is looking at Broadband Over Powerlines (BPL) as a cheap way to get broadband out to neighborhoods or rural areas, you should read this article over at NewsForge, which says BPL still has some issues that have to be worked out.
Among the problems this article raises are relatively high costs, the need to deploy a fiber backbone to support neighborhood level BPL, and radio interference in frequencies used by public safety (fire, police, rescue).
In short, BPL is no shortcut, and may not even be a bargain, compared to other entry level broadband systems like wireless.