Welcome to the board Chumpster. What specific questions do you have about the ELF signals?
From what I was able to find, the signal actually was first detected in 1990, and was later verified to be generated from a transmitter on the Kola Peninsula in Russia. It wasn’t aimed specifically at the US, and was received by Stanford operated radio noise measurement systems in Greenland, Japan, and Antartica. It was not detectable through the normal background noise at Stanford’s California radio noise measurement facility. You can read more of the report from Stanford here. You will need Adobe Acrobat reader to view the document.
As to the purpose of the noise, there are numerous theories ranging from earthquake detection research to mind control, with the most common theory being that it’s some sort of weapons research. Go to http://www.google.com and do a search on Russian ELF Radio Transmissions, and you’ll find quite a few links to the various explanations.
Surpassing ELF in the weapons research department is High-Frequency Active Auroral Research Program, or HAARP. Supposedly far surpassing ELF in power, the US has a large facility in the Alaskan wilderness. You can read more about it here.
Keep in mind that this subject is a fave amongst some conspiracy theorists, so the veracity of the various claims should be viewed with a healthy level of skepticism.