In your home directory there should be a file called ".bash_profile" without the quotes.

use a text editor of choice (if you are using FC3 you at least have vi).

Open a terminal window and type this:
Look for a line that looks like this:
and Edit it to look like this:
Now for this to work you need the Java Virtual Machine installed.

To do that go to java.sun.com
and download the rpm of their site.

When the rpm is downloaded install it by doing the following commands:

Where <rpm-filename> = the name of the file you downloaded.

I used the Develpter package because I code in Java (barely). If you download the runtime environment you will need to change the line above that looks like:
To whatever the rpm adds to the /usr/java directory.

Any questions just post here, I'll answer when I can.