I don't know about Austrailian pro sports but, here in the US, it is a no brainer. You don't do it.
If you pay $20- to enter a stadium to watch professional sport and you're allowed to take you're camera inside. Is it OK too?
If they let you take a camera in then feel free to shoot. I would think that displaying with the intentions of selling would not be allowed.
1. Post photo's of cheerleader & Players on the gallery website, without a players knowledge?
Release....need I say more?
2. Post photo's of fans who know there photo will end up on the gallery website?
In a public place there is no expectation of privacy but, if someone would request that their image not be displayed I would think it wise to remove it.
3. Sell the photo's of the Athletes etc from the site? This could be without the player or clubs permission!
Here in the states, doing that will land you smack dab in the middle of a lawsuit, from the league and the athlete.
I was talking to a pro photographer and he said that you can sell them, but you can only sell the print twice. Then you should DELETE the file!
If you are allowed to sell them then why should you delete the file? Sounds fishy to me, best not try it.
FYI the club is happy for me to place my photo's on my site, but what if I didn't ask permission or if they decided to saying NO?
Will they be happy if your profiting from their trademark, image rights, logo, etc, etc? The NFL, MLB, NBA, NASCAR, IRL, CCWS, NCAA, USAC and every other sanctioning body I can think of controls the rights to their images. There are only two ways you can sell them, editorially or with a license to market that product.
Be advise all of the above information is based upon law here in the states. Laws may vary from jurisdiction to jurisdiction. See your attorney for proper legal advise.
On shooting sports...If you see it happen then you didn't get it.