[CentOS] Managing recompiled packages?

Hi,

I'm using Centos 5.0 on my desktop, and I'm very happy with it. One 
question bothers me. I rebuilt a handful of apps, for example K3B to 
enable MP3 audio, or libshout and mpd, to enable streaming audio.

Now what happens if these get updated? I guess the new version will 
squash my personal version. Is there a way to prevent these packages 
from being updated? Or how should I handle these?

Cheers,

Niki Kovacs