Lately, I have been doing wonderful things with my blackberry. While waiting for my contract to renew so I can upgrade to the 8900, I download the OS (Operating System) 4.5 for my pearl. I can help you get this same OS for your blackberry. Before anything I must say, that most of the later OS are not supported by certain carriers, which means if you need troubleshooting with your blackberry, your cell phone provider may not be able to help you. With that being said, let's move on the steps you have to take.

1. You should download the appropriate OS accordingly to your blackberry.
2. Make sure you have desktop manager 4.2 or later on your PC (sorry mac users, I'm not sure how to help you yet).
3. If you have the desktop manager 4.2, you can skip this step. If not, read on. Download the desktop manager 4.2 and install it on your PC.
4. Click on start>my computer>local disk C:>program files>common files>research in motion>apploader. Then delete vendor.xml file.
5. Plug in your blackberry into your PC. Open your desktop manager. Once this is opened it will automatically detect your blackberry and start the apploader. The apploader wizard will come up and guide you through the rest. Remember to backup, so you can have any stored numbers or programs back with the new OS.

Please note that the new OS will not come with any preloaded wallpapers or backgrounds. Nor will it have any preloaded ringtones.

Also note that if you are using the Colorpearl app, that you will have to delete that app from your blackberry in order for OS 4.5 and later to work. Colorpearl is not compatiable with OS 4.5 and later.