When Xbox Live came out with the feature of being integrated with MSN Messenger users had a need for a keyboard to communicate with their contacts. This involved needing a USB keyboard, possibly an extension cable and lap space for the said keyboard. Well, Microsoft has answered the call of something smaller that integrates with the controller itself, freeing up space and the need for another cable.
The Messenger Kit, or what has been called the Chat pad, is a device that looks like a mini-keyboard that clips in to the bottom of the game pad. It has all the keys that are in the Xbox "Virtual" keyboard that is displayed on screen, you just have to push an orange or green button to pull up the various symbols like "?" or "!". The kit sits flush on the controller, but it eliminates the handles on the bottom of the controller. The kit adds a little weight to the already hefty controllers, but not to the point of being uncomfortable. For darker gaming sessions the keypad actually has a very nice feature of lighting up and the keys have a nice click to them when the buttons are depressed so you know with out even looking that you pressed them.
The original headset for the 360 will not work with it, but Microsoft is nice enough to include a new headset with the kit. It has a standard audio plug in, not the block the originals have for an adaptor. The mute switch is actually inline on the cable, which isn't as nice as the original as you can't just simply flick it with your thumb. The nice thing is that any other headset will still work with the kit so if you have been using a Halo 2 headset or something else it will still plug in with out a people.
Overall the kit fits in a bit of a niche gamer market, but those that send numerous messages over live will most certainly fall in love with the Messenger Kit. The more causal gamer may not like the extra weight in the controller or that it removes the handles on the bottom.