I admire Oscar Pistorius immensely...not only the physical prowess and his determination to be allowed to compete....but he seems like a genuinely nice guy also...

But.....should he be allowed to compete in the Paralympics as well as the Olympics? Is it not unfair to his competition? He spent a long time proving and fighting for his right to be judged in the same way as able bodies athletes, so how can he now compete against non-able bodies athletes? I find that strange

I see him fundamentally as a paralympian who has been given a ticket to compete in the able bodied olympics.
When he competes in the paralympics, he is up against amputee runners who have exactly the same flex-foot cheetah blades, and so I don't see any unfair advantage.

But isn't it "two bites at the cherry"? (apologies to the non-native English speakers! Never really understood that expression)

If a person qualifies for the olympics they may compete. If a person qualifies for the paralympics, they may compete.

I don't see anything wrong if someone competes in both, if they qualify for both, same with any other competition....