Hi Chris

As Steve suggested Maxstrem I thought I might add a little ramble

I have used xbee and xbeepro, they can work out the box, I had them up and running very quickly,couple of hours.
you should get 5000 feet out of the pro version (caveat. as long as it is not in a lead lined box). You can easily mesh them round obstacles, I remember initially running into trouble with the interface from maxstream it is a bit quirky.
If you change the speed of comms between the units for gods sake write something on the unit to tell you what you have done, I have one unit nailed to the wall its associate pin flashing away happily on its own network, I am completely unable to reprogram it and the units do not have an external flash restore to factory settings feature so beware. I am hoping one day that my rogue device will latch onto something nearby so that it will feel it has a purpose in life, I have nearly given it a name. I feel unable to turn off it's life support!!

Also watch out for maximum supply voltage Vdd do not exceed 3.5V ever, but the data pins are TTL tolerant so you can hook them up to a 5V device.

I have found that the chip antennas are slightly better than the whip

do you get the feeling I like them, there are loads and loads of settings that you can alter,which make the units very versatile, however this does require quite a lot of reading, so make sure you have the correct datasheet manual.

I personally prefer to print my manuals and datasheets out in their entirety. I use treasury tags to hold the whole manual together but staple each section as one. The reason I said this is that I initially printed out and prepared the wrong version of the zigbee protocol product manual.

Oh yes, the pitch of the pins, these are a total pain and the only downside to an otherwise great unit, I never solder them directly but use cut down single row header strip mounted on prepared PCB. you are going to have serious difficulty using these on a breadboard..... beware. If it wasnt for the pin pitch I could have had them going before I took them out the box!.

Duncan