Zigbee network for museum security - Final year project

First of all i would like to thank you for you help i appreciate very much! I have some extra information about my project... I want a wireless sensor that it will send a signal to a receiver when the painting is being moved and my demonstrated program(flash,java) will inform me which painting is moved. Can i "connect" a wireless sensor directly to a usb receiver and that relate it to a my program? is that possible or i need to buy extra platforms to get the signal from the sensor and then pass it to my pc? If i can use other WIRLESS sensors than zigbee i believe is fine! As my professor said i just need one or two sensors for the demonstration and if i find a good price for more of them it would be ok!