Red Hat has this thing called the "Red Hat Network", and it has some programs that allow you get get notified when there are updates to your system. Well, it has this little Python script called 'rhn-applet-gui' which places an icon in your system tray. It checks for updates and when one you really need is available, it shows this flashing red "X". I like it, it's a good visual reminder, and I use it at home. At work, however, I couldn't get it to show up. A shows that there are a couple bugs in the applet and a few people have been having this problem. The posts I've seen have pertained to GNOME, whereas I had the issue with KDE. I finally figured out the solution to why it wasn't showing up. You need to provide a place for it to show up. The applet itself is to dumb to figure this out and warn you if it can't display the icon. Here's what you do:

1. Right click on the panel and then go to Add -> Applet -> System Tray. You should have a tiny space/drag bar show up in the panel (probably in the lower right, but if not, then middle-click and drag it over to where you want it).
2. Open an xterm (or konsole, or whatever) window and type rhn-applet-gui &.
3. You should see the flashing red "X".
4. Log out of KDE, and make sure that "Save Configuration" is checked.

The thing that was confusing me for so long was the fact that the System Tray wasn't started. It always has been by default, and I don't know why it wasn't now.

After you've logged back in, click on the flashing "X" to configure rhn-update via the menus. One thing you should probably configure is ignoring the kernel updates. They are good to know about, but you don't want to have them installed automatically anyway. In addition, if you are running a custom kernel, you might get something similar to this notice:

You are running kernel-2.4.19-ac4, but it is not installed in RPM format. It is highly recommended that you run the official Red Hat Linux kernels. By running a custom kernel, you will miss out on any security fixes and functionality enhancements provided by Red Hat Linux, and your configuration is unsupported.

This will appear every time you try to get an update, and it's annoying. Go to "Ignored Packages" and move 'kernel' and 'kernel-source' into the ignored packages area to get rid of the notice.