There are numerous sources on-line for information about curing live rock...I'd suggest a google search as well as a search here on this site. Below is a copy/paste with some info to get you started. If the LR is going into a newly established system you can cure it in the tank(actually thats a great way to cycle a new tank) or you could cure the LR in a new/clean trash can...fairly easy process.
"The Standard Method Used For Curing Live Rock"
"The method most often used for curing uncured live rock is to place it in a completely separate, unlit (to prevent algae bloom problems), heated ( compare heater prices), well filtered aquarium with powerheads and a protein skimmer ( compare prices.) for at least a month, but before doing so clean and prepare it by striping the rock of all organisms that are dead or dying off. Once the rock has cured, it can then placed into the intended aquarium for aquascaping aquascaping. For most hobbyists, this type of curing process may not be practical. For those on a tight budget or that don't have the extra room, it may not be feasible to have a complete separate tank running just for this purpose. However, you may be able to swing this type of set up using a suitable sized container such as a large plastic garbage can. And, course you do have the option of ( cycling uncured live rock directly in a newly set up tank, if need be. So how can you tell when the live rock is cured? Simple. When it doesn't smell anymore, and your water test results for ammonia and nitrite are normal again. This means zero readings on both."
Off topic just a bit but I once lived in Cape Girardeau...its nice to see a fellow hobbyist from the old home town.Matter of fact this coming Saturday or Sunday I may be there for a short visit. Sure do miss summers at the ball park...great place to watch baseball...college...the Capahas...local Legion teams....