Seeing i wrote this at 'another' forum here it is cut and paste:
HOWTO: upload midlets (third party software) to your blackberry for all, even BWC!
I hope the moderators don't mind, but this procedure will show everyone how to upload third party software (midlets) to your blackberry. Midlets are java applications written for phones under the MDIP specification. There are hundreds of midlets already available to try, from network-enabled applications such as telnet, ssh, vnc, instant messagers, to games!
Where to download midlets? using Google, i come up with: http://midlet.org http://www.javamobiles.com/midlets/
Search around for more..
Who needs to do this and why? We all want more third party software for our Blackberries, and this adds hundreds of potential titles to our third party software base! The folllowing scenarios are Blackberry users who benefit from this procedure:
a) All blackberry users without BES, such as BWC users
b) Blackberry users who use the redirector
c) Blackberry users with BES lower than 3.6
If you have BES 3.6 or higher running, you can download JAR/JAD midlets directly from your blackberry browser, as the BES does the conversion to COD for you automatically. However, you can still do this procedure if you really need to..
What technical requirements do I need to perform this task:
a) You need to be comfortable using DOS
b) You need to download and install the Blackberry JDE (free from the rim developer website)
c) You need to download and install the Sun Java SDK 1.4 or higher.
d) You do NOT need to know how to use the Blackberry JDE, you merely need some of the DOS apps that come with it.
Here's how to convert and upload midlets (JAR/JAD) files to your Blackberry. This is not for the faint of heart, but any person with reasonable technical computer skills can do it:
a) Download and install the RIM Java Development Environment.
This software requires the sun Java SDK, so
b) Download and install the Sun Java SDK. http://java.sun.com/j2se/1.4.2/download.html
MAKE SURE YOU GET THE SDK! *NOT* THE JRE!
Once both are installed, download the midlets you wish to put on your blackberry. Midlets are BOTH a .jar and .JAD file.
c) For ease of use, move the JAD and JAR files for each midlet you want to convert to the BIN directory in the RIM Java Development Environment directory on your hard drive, for example:
c:\program files\Research in Motion\Blackberry JDE 3.7\bin\
Using RAPC.exe in DOS, convert the midlet to a COD as follows, all on one line (might be easier to make a .bat file out of this)
d) rapc import="c:\Program Files\Research in Motion\Blackberry JDE 3.7\lib\net_rim_api.jar" codename=virca -midlet jad=Virca.jad Virca.jar
Subsitute a different codename, jad and jar filename for whatever application you wish to convert. If successful, it will say no errors and you will have a COD file. The import= is a REQUIRED step.
Using javaloader.exe from a DOS prompt to upload the newly created COD file to your blackberry (in my case a USB blackberry)
e) javaloader -usb load filename.cod
And that's it! An icon will appear in your ribbon. Give it a try and see if it works. Not everything will work, but most do. Mileage wil vary..
a) If you use the application loader at a future date, the loader WILL remove your midlets as they are not known by it. You will probably have to re-upload them again in this case.
b) Make sure you have enough free space to upload the applications..
c) If something goes wrong, Be sure you are familar with the RAPC or Javaloader.exe documentation. If not sure, use google to help you.
d) If you can, Test your Blackberry JDE on a sample application. Compile, and run a sample app in the simulator to ensure that your JDE functions correctly.