Throwing a football (properly) is very close to Mike Marshall's motion, applying force in a straightest possible line with little forearm flyout. Actually, probably closer to throwing a javelin. Using a non-Marshall motion uses centrifugal/centripetal (rotational/angular) forces to produce velocity. There is certainly rotation happening in throwing a football, but the goal (or mental cue) should be to stay compact and drive the ball as straight as possible towards the target.
As far as the release is concerned, it's very close to throwing a slider. The last finger to touch the ball is the index. The palm isn't exactly facing perpendicular towards the head. I would say the main fingers used to throw a football (thumb, index, and middle) are actually "behind" the ball at release. The ring and pinkie are mainly just for support, just as they are for a baseball. Also, there is/should be pronation upon release. Pronation will help impart more/proper spin. Supination is the incorrect way to release, unless it's a shovel pass or something short and requires more "touch". But let's just focus on what happens on a "bullet" pass.
I'll see if I can find any video and put something together. Currently in the NFL, the hardest throwing QB's are arguably Jamarcus Russell, Jay Cutler, Byron Leftwich, and Michael Vick. Brett Favre can still sling it as well for an old-timer.
One thing about throwing a football is that by just looking at the quality of the spiral, you can tell immediately if the proper mechanics have been used. Of course, it's shape certainly helps. For a baseball, you'd need high-speed film to see the spin. Throwing a football may help for those who want to get a feel for how a slider/cutter should be released.