If you haven't seen it yet, there is an awesome youtube video: Distance Shootng with an Englsh Warbow. Check it out.
Wide stance, draw "into the bow" (use your entie body, not just your arms), feel your shoulder blades come together, use the whole arrow, bend your knees, sit back from the waist, loose, and follow through. Shooting in the bow feels a bit like you're arching your back, and sticking out your butt.
As I understand it, there are two ways to do this: a rolling loose, and a sustained loose. A rolling loose starts with the bow flat, and you roll foward and up, loosing the arrow in a smooth forward motion, with the archer often stepping forward to follow through. For a rolling loose, check out the video on the EWBS website. The above youtube video I already mentioned, describes what I call the sustained loose. Which technique yields more distance is up for debate, but I believe the top warbow shooters use a rolling loose.
I'm sure Steve will chime in on this, giving much more detail.