The Maxstream development kit is well worth the investment. With the software you can walk around and test all your locations for receive signal level. That way you can determine which module to buy, the best place for the master or if you need a repeater. There is lots of support on the internet for the series 1 modules. You will need an adapter for the 2mm connector, got mine off of eBay and 3.3 VDC.

http://www.maxstream.net/products/xb...kit-zigbee.php