This is one of these posts that if you follow the instructions, you do it at your own risk 
Mobile phone networks when selling phones often brand them with their modified version of the software to put logos on them and restrict access to certain features etc... This can be a pain sometimes as you cannot get certain features such as VoIP if you are on a certain network. Branded phones are often cheaper as they are purchased on contract. In the UK you can usually pick up a decent phone for free on a 12 - 18 month contract and in some cases even get a PSP or XBox 360 thrown in also.
Symbian Central have created a guide to allow you to remove the branding of a mobile phone (Nokia N95 and other series 60 phones).
The instructions can be found at the link below on Symbian Central. One word of caution. When you use a USB cable to connect to your PC it is best not to touch the phone, computer or cable as they have very dodgy connections on some phones and can disconnect at the slightest movement. Also it is good practice to have a full battery as it would suck to see the phone go off mid way through the firmware update.
Via: Symbian Central