I finally decided to hook my pc up to my HDTV using a DVI-HDMI cable. The screen loads up just fine, other than about 20 pixels being off the screen around the entire picture. When I hook my tv up using a vga cable, the picture quality suffers, but it is all there. I am relatively new to linux in general, and have no idea how I need to edit my/etc/X11/xorg.conf file to get my tv to work properly. It is an Olevia 227 27" HDTV.

If you're running Myth, you don't need to touch your xorg.conf unless you want to use the desktop (I don't, Mythfrontend is always running). You can go into Mythfrontend's Setup/Appearance menu and tell it to run the GUI at a different size than the desktop, then shave those 20 pixels off of the x/y settings and adjust the offset so the GUI just fills the screen.

I do this with component out and find that when playing recordings on the TV it works out decently because the overscan is not enough to notice (the networks scale the pic for it), and you never see the annoying close-caption digital junk (scattered white and black dots) at the top and sides of some channels.

If you're not running Myth, you will indeed need to explore the various modeline options out there. Google for Olevia and modeline and see what comes up.