Barclaycard's Football Credit Card:
<a class="postlink" href="http://www.barclaycard.co.uk/champion/football_credit_card.html" onclick="window.open(this.href);return false;">http://www.barclaycard.co.uk/champion/f ... _card.html</a>
You buy your season ticket on it, and the balance is interest free until you pay it off, providing you meet minimum repayments on it, as you'd expect. It's basically an interest free loan.
I did it last year, and it's true, it's kosher, and very, very, handy. However, the UEFA Cup kicked in, and I started loading money on it, and then the interest kicked in.
But if you just buy your season ticket on it, then rip up the credit card, you're fine. I would recommend it to everyone.