I just want to read information from sensors

Hi im new in arduino. I read some quick manuals and FAQ for arduino and i think arduino will be my solution.

I just need to read information from sensors. I need it because i want to make myself home-made alarm.

This mean the sensors will be default closed (the sensor: upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Reed_switch_(aka).jpg/271px-Reed_switch_(aka).jpg) so when somebody open the door, the sensor will be opened.

Can i read this from the sensor, like normally closed or opened?
If its possible to do that, then i can make some software and connect arduino to my linux box with serial or usb cable, then i will loggin to linux console and be able to read information about arduino pins.

Can somebody give me more info about that?

Seems possible, yes.

Maybe you want to look at this:-

It is some ready written software that removes the onus of reading and transmitting data from the arduino programmer onto the host computer via a language called processing.

It can make things simple but will not allow you to have a stand alone system because your computer always needs to be on.