Hi Jorge,
Bill is right. One way to do it is to wrap the page in a table, creating something similar to frames.
However, there is another way.
If you look at the "menus" example, for example, it's fairly easy to make a "left hand menu" (which is still part of the header tag) and then have the browses and forms etc appear to the right of the menu. I'm doing this at the moment in a couple of apps. Sometime soon I'll write up the process.
Part of the reason I needed to do it was because the menus I'm using are somewhat dynamic. That is, I wanted to be able to change the text on some of the menus, depending on which browse (or indeed browse row) was selected.
Things are a bit hectic right now, but I'll try and write this up sometime soon.
cheers
Bruce