getting paid: what recourse does a freelancer have with an on-line publisher?

I'm a free-lance writer working under a contract with an on-line magazine publisher who appears to be going under, based on a host of clues I won't detail here.His business address as it appears on the homepage does not apparently exist on the ground, nor can Information 411 give me  the telephone number listed that appears on the website's home page.  A phone call placed during business hours got a message that "The office is closed, please leave a message."  He lists the address as Boston, yet I understand from other writers that he is actually based in Denver.He now owes me around $1,000 and keeps reminding us to submit our pieces and invoices on a regular basis, yet they do not appear on the site when they are submitted, nor is a check forthcoming despite promises he'll "send a check."  He is now long past the 60-day payment period stipulated in the contract.What recourse do we writers have in this situation?Thank you.