If you need help with specific language for inclusion in your subpoena/court order/search warrant, contact FaceBook before sending it and they will assist you. The contact info is on the web page.
If you need more help, the NDAA/APRI has some excellent publications available for free download to guide you through the murky waters.
For all non-public info on Facebook, the best practice is to use a search warrant, rather than subpoena, in order to comply with the Electronic Communications Privacy Act (ECPA).
Facebook will preserve the account in the meantime, by request via fax, email, or letter.