Lyx & figures

I have created some network topolgy's using
Dia, exported them as .eps files, yet I am having
a difficult time inserting these images into a Lyx
document.

Is anyone using Lyx enough to give me the
skinny on what works best for images in a Lyx doc.
Also, are some classes just not able to display
graphics/figures (e.g SGML article)?

v/r
Mike