hi frnd,
i need a help for my final year project... i want to form a wireless sensor network using Zigbee and PIC.... suggest me how to do? suggest me some modules with their drivers... plz... its urgent

Digi (formally MaxStream) has very nice ZigBee modules called XBees. They are 3.3v and use a simple UART communications protocall. They range in price from $20 to $35 each last time I checked. They also have adc inputs and GPIO. They can easily be used for wireless sensor networks. They also have different antenna options for different applications. I've used their Xbee Pro modules with great success. I can get full data rates (250kb) at a range of 1km LOS with a 1/2 wave dipole on the mobile station and a short backfire antenna at the base station. With a little coding, you can also create strings of them to increase the range.