How do you download from RHN (RedHat Network) just one particular rpm (and its dependencies if needed) using up2date? Thanks for any help you guys/gals might give.

As root type: up2date --install foo --solvedeps=foo

If you know the name of the package from command line you can type
up2date-nox --install <package>

The "up2date-nox" tells it not to start the GUI.

To find the package you're interested in you can type:
up2date-nox --whatprovides <whatever>

Where <whatever> is something descriptive.

Note this is much like grep through all packages so you can get lots of hits if you don't make it specific enough. e.g. If you typed "ls" for <whatever> it would find the package that contained "ls" but would also find all files that had "ls" in their name such as "alsa" which really have nothing to do with the command you were looking for. Make sure whatever you're looking for is as specific as possible.

You might want to look into yum instead of up2date. It is becoming (or has become) the standard tool for RH based package management.

As of RHEL5 yum is the only way to do it. Before RHEL 5 though the "approved" method was up2date.