An informative blog on the subject of DMCA take down notices by a lawyer specializing in representing photographers:

When you find your work being infringed, the first step is to find out whom to contact.

Both these places will let you search for the ownership records, including the registrar of the domain and the administrative contact. You will also see the names of the servers where the domain is hosted.

Notwithstanding our sample DMCA notice, hosting companies vary widely in the "acceptable format" for DMCA take down notices, as well as how they will receive them, i.e. eMail, USPS, fax, certified mail, etc. In addition, specific instructions for each hosting company can be difficult to find, but using their preferred formats will facilitate getting your material taken down or blocked. As we locate this information, we will link directly so you can more easily make your complaint.

Go Daddy

Host Gator

Others will be listed as we obtain them.

Caution! Making false DMCA notices can result in you being sued. Make sure you have your facts straight.