hi guys, I'm new with zigbee i need you to help me learn about it and know how to implement an embedded system using it thanks in advance
One good place to look is on the Digi site. They have several products to help you, including embedded development kits.
If you want to go Open Source, look at Source Forge. They have some open source stacks. I have not used any of them, so I cannot comment beyond knowing that they exist.
Depending on your needs, you might want to just look at XBee, which is a subset of zigbee. There are some nice development tools for XBee. I have used an XBee expansion shield with the .net micro framework and boards provided by TinyCLR to do a wireless prototype.
Creating a zigbee stack on your own would be a fairly large task, so only you can determine if there is ROI in doing so. I would be more inclined to buy it in.
Get a ZigBee Starter Kit. Lots of vendors provide one; gust Google that exact phrase.
For example: AVR 8-Bit RISC - IEEE 802.15.4/ZigBee - Tools
Or you can ZigBee on a PIC/Microchip at very low cost. http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2112
I would also have a look at TI's offerings RF/IF and ZigBee® Solutions. As well as what Jennic has to offer.