This program should work (theoretically) on any WM devices, Smartphone or PPC, with OS 2003/2003SE/WM5, as long as the device has MS Bluetooth Stack. Tested on Voyager, XPhone2, C500, C550, Tornado, SP5, XDAIIs (thanks to those who have spent time in testing this one.) It also works in landscape mode on Pocket PCs.

The program automatically determines if your device is using MS BT Stack. If it doesn't, it will prompt you at start-up.

This doesn't have an AI. The main purpose anyways is for you to play with another WM device user.

By the way, for those who want to try this and doesn't have anyone (WM device user) to play with, you could try playing between your WM device and your desktop/laptop. Your BT device on your desktop/laptop should have MS BT Stack. If it doesn't, just follow the procedure below:

1. Disconnect your Bluetooth device from your desktop/laptop.
2. Uninstall the software that came with your BT device. How? Go to Control Panel>Add/Remove Programs>And choose your Installed BT Software. Or alternatively, Go to Control Panel>Bluetooth Devices>Click Hardware Tab>Click Properties>Click Driver>Click Uninstall button.
3. Re-connect your BT device on your desktop/laptop. WindowsXP should recognice the device and you should let Windows install the Bluetooth stack by itself (don't install the software that came with your BT device.)
4. Download the zip file below.
5. Unzip on your desktop/laptop.
6. Run BTChess.exe and see if the program recognizes your BT Device. Your desktop/laptop should have the .Net Framework installed. You can download the latest version of .NET Framework 2.0 Redistributable in case you need it.
7. If it does, then your BT device has MS BT stack installed.
8. Try playing. :-)

How to use BT Chess?

1. Make sure that both devices are running BT Chess.
2. Upon start-up of the program, you may opt to Turn on your BT (and optionally set it to "discoverable" mode so you could be invited by others running the same program.) Unless you turned-on your BT device, your Menu Option to Start a New BT Game will be disabled.
3. If you don't turn-on your BT device, you may be able to play a Solo Game. Since there's no AI, however, you play with yourself in this mode.
4. If you have your BT device turned-on, you can invite other BT-enabled device running BT Chess by choosing Menu>New Game>BT Game> and choose to either Play as White or Play as Black. Alternatively, if your device is set to "discoverable," you may be invited by other users.
5. Once you have chosen to play white or black, the program will search for other BT devices within range. Just choose from the list with whom you want to play with.
6. The other device running BT Chess would prompt the user that you have invited him/her to play chess. You will then be prompted if he/she accepted the invitation. If he/she does, the game starts.
7. NOTE: if you didn't get a response, the other BT device probably is not running BT Chess on his/her device.
8. NOTE: if the other device is currently engaged in a BT Chess with someone else, you will get a prompt saying that he/she is playing with another player.
9. For PPC users, you may use the stylus or the navigational pad in playing the game.
10. For Smartphone users, you may use the navigational stick or your keypad to navigate. Your keypad is used as an 8-way navigational pad with 5 as the action key.
11. Once engaged in a game with another player, the menu option Accept BT Invitation is automatically "unchecked." In this case, you will not receive any invitation from other BT Chess users within range. However, you still have the option to "check" this one and be able to receive other invitations while engaged in a game.

Note:
If you want to receive invitation to play only from those BT devices you have already "bonded/paired" with, don't set your BT to "discoverable".

Installation:
Just download the zip file below, unzip on your PC, transfer to your device (Smartphone or PPC), and run BTChess.exe (you have to manually create a shortcut on your Start/Programs Menu).