Do i need a certain mac to develop ios apps?

Is the iMac All in One A1224 20 Desktop (Intel Core 2 Duo 2.66Ghz 320 GB Hard Drive, 4096MB Ram, DVDRW Drive, OS X 10.5.2) suitable for developing apps?

I have never owned a mac before and I want to start developing IOS apps, games in particular. I'm not sure whether I need a very expensive mac with very high specs, or will the mac specifications I have listed above be enough for developing? If there is recommended mac for this subject, please tell me.