Well the magazine info is the most info you'll find. Some people have repeated it here, but there's no thread for the contest. The other contest mentioned has yet to be properly announced I think. Now that I read the post again, I think the winner gets featured on the IFX website front page. Under The magazine, comments and suggestions, Image of the day replacement thread, Hacksaw says:
"And as for whoever mentioned putting compo winners there, well get your quills poised, as we're soon going to have another Christmas image compo to fill that slot over the Yuletide season!"
("the slot" being the featured image here on the website)