Symbian Series 60 SDK from forum.nokia.com
Symbian UIQ SDK from developer.sonyericsson.com
Maemo SDK from maemo.org (Nokia N770, N800 tablet pc)
J2ME from java.sun.com
DevRocket from Montavista
OpenMoko from OpenMoko
(also mokomakefile project, sdk for linux)
Google Android from code.google.com/android/
BlackBerry JDE
(RIM Java Development Environment)