Well I can help you with at least a bit... PoE stands for "Power over Ethernet". In other words, it allows the shield and Arduino to get power from the ethernet cable so they don't need a dedicated power supply or battery.
If by "infra mode", you mean using infrared transcievers for wireless communication; I'm not aware of any Ethernet Shields that incorporate that feature. However, you should be able to add that functionality to your device using either an additional shield or custom circuitry.
Also just a general piece of advice, in the future please don't type the thread title in all capital letters. It can be considered rude.