Gas Sensor/Arduino newbie

Hello, I'm new to Arduino and basically new to all this. I've assembled a robot starter kit that was based on one of Atmel's microprocessors. I never programmed it myself, I just had a look at the source code but I understood what it did. I'm familiar with C# on windows and I think I will have no problems with the syntax.

I'm thinking of creating a gas-analyzing tool as a schoolproject. I have no one around at home or at school that can help me so I have to rely on google and possibly you. So my first question, is it fairly easy to extract the data and get the proper units and such for a beginner?

I was thinking a sensor like this: pololu[dot]com/catalog/product/1633/resources .(I'm not allowed to post links for some reason)

Is it possible to tell the gases apart? or does it just detect if there's one of those gases within that range and sends it back? and how do you extract the data?

Are there any good guides that you could recommend?

I need some help before I purchase my Arduino and sensors.

Thanks. I'm sorry if there's a thread like this.

I would like to make an Arduino read how much there is of certain gas types in the air.

Im new to this but when I look at this it seems like the sensor is capable of detecting more than one gas? is possible to tell them apart? What does this sensor send back to the arduino?

That sensor is designed to sense methane. However you will get a response from other gasses as well. The graph shows what other gases will do.
It will not give you the composition of a mixture of gasses. There is no way to find this out with this sensor or indeed probbly a sensor you can afford.

If you have one gas and you know what it is you can determine the concentration of it using this sensor.

Beat be to the draw Richard.