...I recommend [link|http://www.lyx.org/|LyX] for documentation on Linux.
You don't need to worry about things like margins; it obviates that need entirely. No such thing as "center" -- you just choose the style of formatting to apply to the text (from a limited, but very useful list), and away it goes. The LyX language is derived from TeX/LaTeX, so it's easily converted to, say, PS for final printing output...
It's not the easiest thing to install, but once you get it up and running, it's pretty damn slick. At work, I've got a document that details how to install it (at least for RH 7.0). Lemme know if you want it...