Horizontal and vertical centering in HTML?

I want to center my Flash file right in the center of the persons browser window. Horizontal centering is easy simply using “Center Justify”, but how can I center it vertically as well? Is this possible? One big reason I want to do this is the size I have chosen just barely fits a 1024x768 resolution. I had thought about having a splash page with an enter graphic then having Dreamweaver open a new browser window (the dreaded popup) and having the poped up window get rid of all the nav bars, status bar, etc…

Any suggestions from you more experience web guys/gals would be much appreciated. This is going to be a portfolio site, which is part of the reason I thought it might be ok to open a new exact fit size window with no bars or anything. Alternately I thought about having it go fullscreen. I just want the site to fill up as much of a 1024x768 res setting as possible because the smaller my site, the smaller the images will have to be to fit inside it.