ANDROID Useful software
I happen to own a SonyEricsson Bluetooth watch MBW-150 which has server me well for several years. I bought it originally for SonyEricsson P990i. After that I have been using it with Xperia X1, Nokia N900 and now with Samsung Galaxy S i9000. All this thanks to OpenWatch application found from SmartMadSoft. You can find this application in Android Market, but more recent versions are in beta.smartmadsoft.com.
Installation is easy. If you download it from Android Market, installation is automatic. If you download it from beta, then you have to click the downloaded file to start installation. After this just pair the watch with phone. Launch OpenWatch and then in menu press Start. Now you can see and feel (vibration) notifications on your wrist. You can also launch and control the media player using buttons on the watch.
In settings you can enable/disable what notifications you want. Available options are e.g. K9 Mail, Gtalk, Calendar, Alarm clock and Twitter. Track info is also displayed. If you are using Galaxy S i9000, then check that in settings you have
Package Name = com.sec.android.app.music
Class Name = com.sec.android.app.music.player.activity.MusicPlayer
Downside is that you have to have Bluetooth on all the time, which means that battery depletes more rapidly. I have found out, that usually you can still manage through the day without need to recharge Galaxy.