By using the BlackBerry Java Development Environment you can simulate a BlackBerry device on your Windows machine:

The BlackBerry® Java™ Development Environment (JDE) is a fully integrated development environment and simulation tool for building Java 2, Micro Edition (J2ME™) applications for Java-based BlackBerry devices.

It is a Mobile Information Device Profile (MIDP) compliant J2ME environment for developers who wish to maintain seamless portability in their wireless applications. In addition, the BlackBerry JDE provides a full suite of interfaces and utilities to take advantage of some of the unique features of the BlackBerry device.

Mac or *BSD version anyone? :(