I've been reading a lot of posts on the forums lately and a technique keeps on popping up "point-first" when throwing glands, by what ive gathered, it's effects are the same as throwing a football with a perfect spiral. But i'm wondering how could you achieve that with a sling, i mean you can't exactly throw the sling like you are a football.

This is from David Morningstar:  
You need to have a wide grip (retention cord on middle finger at least) so the cords are well separated. This will get the pouch to follow the orientation of the hand.  
This is a quote from Brian Grubbs:
As David has stated, a wide grip is necessary for reliable rifle spin.  The orientation of the hand on release on an overhand throw decides whether you get backspin of rifle spin.  If you palm faces forward on release, you will get a rifle spin.  If the hand is facing toward your head then you will get backspin.  
   With me it just sort of happened.  Like benkolmer wrote, once you have it you have it.  I would find it difficult to sling without either a rifled or backspin at this point.   I get it with all overhand styles.  I get a mean topspin with underhand.

Greek overhand and figure 8 give you a rifle almost naturaly.
 
The most concise way to explain it is to just enure that when you release, the inside of your wrist should be pointed towards the target. This means you just have to tilt your wrist back a little with side arm type styles.  
 
Rifling can really help when slinging most ammuntion. My next ammunition endevor is to make some concrete glands with a pointed metal spike (nail) sticking out both sides so I can use it on archery targets.

I always thought that too, Aussie.  Have you ever tried it the other way, with the ammo in line with the pouch?  I get the desired spin either way.  In fact, the projectile seems to go farther when launched in line with the pouch.  Give it a try and let us know if you get the same results I did please.

I find that if the style itself doesn't give a decent rifled spin, a twist/rotation of the wrist during the release will usually do it. (It's basically the same principle used to put a spin on a bowling ball)  
 
 
For example: since I usually sling sidearm or overhand, I rotate my right wrist counter-clockwise immediately before releasing.
It naturally sort of happens subconsciously now. Once you understand it, it just sort of magically happens automatically.