"This web site provides information for the public to contact broadband over power line (BPL) operators with systems deployed nearby that may be causing harmful interference to communications services."http://www.bpldatabase.org/This database has been around since 2005 but access to it was very restricted. The ARRL filed a complaint with the FCC and these restrictions have now been lifted. You should be able to enter your zip code and search for a BPL operator or simply click the BPL System Listing link and get a list of all of the operators in their database. Theres some interesting information there including the HF/VHF frequencies that these systems operate on.
If you haven't heard BPL, heres an audio clip of what it sounds like on your receiver in the AM/SSB/CW/FM modes.
http://www.cq-vhf.com/BPL.mp3Sam / KS2AM
