I found this in LinuxQuestions.org:
http://www.linuxquestions.org/questions/susenovell-60/how-to-build-rpm-in-10.3-594066/?highlight=build+rpm

I know this is for SuSE but there should be a buildrpm package for your system. Anyway, it refers to this tutorial from Novell: http://en.opensuse.org/SUSE_Build_Tutorial