I'm trying to figure out how to send you the code I used, but it won't keep its text formatting on the message board.
If you want to, send me a PM on XOOPS with your email address and I'll send the instructions to you.
Basically, it just a matter of creating a table containing the topics you want and opening up the theme.html for whatever theme your site is using.
Once you're there, look for "xoops_contents". It should be between a < div > < / div > tag under all of your center, left-center and right-center blocks.
Put a couple of line breaks after the final < / div > and place your table with your categories there.
It's a lot less confusing than it sounds. If you have any problems, feel free to contact me.