You need to specify more information. Zigbee is not only a protocol but also a wireless standard similar to Bluetooth. I would imagine you need to share with us what sensors you wish to use and what type of data you wish gather/log/share with your web server.

Then you will need to select a Zigbee bridge hardware to work with a PC Server to talk with your wireless sensor network.

Start with that research and see where it gets you.
- Ben