How to choose a mirror for up2date

[Olaf Eichhorn, VB Pfeifer]

I have an really linux newbie question ;-)

How can I use an mirror to get updates via up2date?
I have only an modem dialup connection at home and the downloads from 
Red Hat (US) are very slow. There are several german mirrors wich I 
would prefer.


thanks for help

Olaf