Title says it all. The Android 4.0 Ice Cream Sandwich multitouch keyboard is ported to work on other Android phones. Should work on all 2.2-2.3 (Froyo and Gingerbread) devices with WVGA/qHD screens. Not sure about lower resolutions, but I think those will get cut off. The typing feature, suggestions and corrections work, but voice input is missing. If you can live without voice input, it's a great keyboard. Auto-correct has been improved tremendously over Gingerbread. Download from Market, video demo of it on a non-ICS device below.
Get Ice Cream Sandwich keyboard on any Android phone (video)