Multi X-session setup

[tech at tnet.no]

Hello.

I don't have this equipment yet, but I will get it later today hopefully.

Motherboard: MSI K9AG NEO2-Digital, AMD 690G+SB600, Socket-AM2, ATX,DDR2, DVI+HDMI, PCI-Ex16 with integrated ATI Radeon X1250 GPU.
PCI-Expreses video-card: Sapphire Radeon HD 2400 PRO 256MB DDR2, DVI-I/Tv-out/HDMI

What I want is two have two seperate X sessions, with two displays, one with tv or projector, the other my LCD monitor. Also, only one set of keyboard and mouse.

The tv/projector one will be mainly be used to view high-quality video (1280p or 720i in xvid or x264) through mplayer, the other monitor will just be for general stuff.

I want the video/picture at the X-sessions to be active at the same time, but with ability to switch between what X-session mouse and keyboard will be active/controlling to.

I know there's an option for dual screen set-up, but this is not something I quite feel comfortable with.

What driver that will be used for whatever card is not something I worry about either, I don't mind if there's two different drivers or if any of them is closed source.

Is this possible and if so could someone hint me to how to do it, either in an explanation or a reference to documentation? 
If it is not, could someone please list similiar options I could try?

Thank you.