I do agree with Myka that if not done properly, fresh rock has potential to be a hassle. The ideal would be to cook it, but if you're interested in retaining the 'critters' and macros and stuff, there's an excellent thread on NR about soft cycling properly... I'll have to find the page.
Found the thread, this is sort of the guide that I'm using...
http://www.nano-reef.com/forums/inde...owtopic=180442