[ema_rocca]

You might want to give a try to apt-cacher-ng.

apt-get install apt-cacher-ng

[cdjk]

I use this - and it's great with my slow internet connection. It's totally transparent, and I only notice it if my vm running it is down.

And despite the name, newer versions work with yum too (although I found I had to disable the fastest mirror yum plugin to get reliable caching).