The basic steps of the upgrade/update (those words are interchangeable here) are very simple: If you haven't already, install the Desktop Manager software that came with your Black Berry Storm.
There is no charge for this system software upgrade.
This is something RIM implemented with the latest updates to the Desktop Manager. For BES users, your IT needs to issue an activation code unless you can generate one yourself or have Desktop Manager set up with the BES option, it will do it the next time your run DM.
Official OS install: To load an official OS, all you need is to download and install the Desktop Manager.
Before updating your phone's software, it's recommended that you back up the phone memory.
Click here for information on how to back up the phone memory.