I have 2 Arduino Uno's, 2 Xbees and 2 Wireless Proto Shields. The first setup has a humidity/temperature sensor (SHT21P) and it writes data to serial and it works (i've tested it). Now I have the other Arduino with shield and Xbee- plugged in PC to get data from the sensor. So here's the problem- as far as I understand I can't use Xbee and Arduino at the same time, because USB and Arduino both use TX RX pins to communicate to PC/Xbee. I've tested both of the Xbees when they are powered with DC jack and they both work. So can anyone confirm that it's true that they're not made for being used by PC and Arduino at the same time? If so- how can I get the data to my computer?

I have 2 Arduino Unos, 2 XBees and 2 Wireless Proto Shields. The first setup has a humidity/temperature sensor (SHT21P) and it writes data to serial and it works (I've tested it). 

Now, the other Arduino with shield and XBee is plugged in my PC to get data from the sensor. So here's the problem: as far as I understand, I can't use XBee and Arduino at the same time, because USB and Arduino both use TX/RX pins to communicate to PC/XBee. I've tested both of the XBees when they are powered with DC jack and they both work. So can anyone confirm that it's true that they're not made for being used by PC and Arduino at the same time? If so, how can I get the data to my computer?