If you are an American or Canadian applying for a visa to travel to Libya, you must contact the Libyan Embassy in Ottawa, Canada. This is the only embassy that can process visas for Americans. As of March 2006, there is no diplomatic embassy in the United States.
Here is the website for the Libya Embassy in Ottawa. You can find all the details and documents for traveling to the country. The phone number is 613-216-0136. If you get a voice mail, it will start in Arabic and eventually will give you options for English.