I plan on buying an Xbee so that i can control my Arduino using a wireless network,is this possible because when i googled i see people using two Xbee's to communicate with the Arduino and for me I dont hope to buy all those two XBee's.I am sorry if this sounds like a stupid question,I dont know so I am asking.
The XBee is a transceiver - a transmitter and a receiver in one unit. It needs to have something to talk to. One XBee by itself is pretty much useless.
if you want, you can purchase a Roving Networks RN-XV xbee shield plug in replacement that allows you to connect it to your wifi network and control it either from an ios device or your computer wirelessly... 
might be something for you to check out there are several threads on using it in various scenarios
Hope this helpds