To do this you need

1- So first step download JDE
http://na.blackberry.com/eng/developers/downloads/jde.jsp
and install it
I use JDE 4.2.1 but 4.3 should wrok too

Install JDK from java
http://java.sun.com/javase/downloads/index.jsp

After go in the directory
C:\Program Files\Research In Motion\BlackBerry JDE 4.2.1\bin
(If you installed it on C:/)

2-Download application from your blackberry
(Plug your blackberry on your PC)
javaloader -usb unload game.cod
to know the name of the game or application go in parameters->advanced->applications
go on the application and show properties
You should now have .cod in /bin directory

3- upload your .cod on another black berry using javaloader

(Plug your blackberry on your PC)
C:\Program Files\Research In Motion\BlackBerry JDE 4.2.1\bin>javaloader -usb load game.cod

4- To delete the application use javaloader again

javaloader -usb erase game.cod


I have do it with Might and Magic 2 for 8100