Installing software from RPM using YUM

I'm trying to install a software. YUM didn't not have it, but I found the RPM from freshrpms.net. However I got following error:

# yum localinstall <<<some rpm>>>
.....
Downloading Packages:
warning: rpmts_HdrFromFdno: Header V3 DSA signature: NOKEY, key ID <<<some hash>>>
Public key for <<<some rpm>>> is not installed


I don't know whether the RPM is missing the key (but harmless) or it is bad/corrupted. I'll just install the software from source code.