Why would you want to do this?
When new firmware is released, Nokia will only release the vanilla, or un-branded, firmware. This means that only unbranded (non-network specific) phones will 'see' it when running the update tool.
The firmware goes to the networks who modify it by adding their logos or themes (and in many cases disabling certain apps 😡 ) so that is why it often takes weeks for the network specific version of firmware to roll out. Changing your product code allows you to 'fool' the updater into thinking you have an un-branded phone and thus get the update sooner, without all the memory sapping themes and crap and with all the apps intact.
Is there a risk of damage?
No. There is a small risk associated with updating firmware but changing your product code does not add any additonal risk.
Does this harm my warranty?
If your phone is still within the manufacturer's one year warranty (or any extended warranty) this will void it. However, many of us on this forum have changed the product code and subsequently had the phone repaired at a service center under warranty. There is a risk they may discover you have done this and refuse to do the work under warranty but the risk is very small. There is also the moral question, but that is up to you!
Ok, I'm cool with all that, how do we do this?
To change product code you need Nemesis Service Suite (NSS): http://www.b-phreaks.co.uk/software.htm#downloads
[LIST=1]
[*]Install NSS and, while installing, accept the default for 'Virtual USB'.
[*]Once installed, connect your N95 to the computer by usb cable.
[*]Run NSS
[*]It wil be pretty blank at this point. Hit the magnifying glass to search for devices

[*]Once that is done (a couple of seconds) click on the Phone Info button and then, on the right hand side, click Read

[*]You will now see your product code which is a 7 digit number. If you plan to change this back after flashing then make a note of the current code (this is probably wise to do anyway although it is written under the battery in the back of the phone).
[*]Take a look at this thread and choose a product code you want to use (remember the codes for the N95 'classic' are different to the 8Gb). The code for EURO 1 is generally recommended for the classic N95. Obviously you don't want an operator specific code!
[*]Delete the current code and type in the new one in the Product Code box in NSS. Tick Enable and then press Write
[*]That is all there is to changing your product code. Easy huh?
[/LIST]
Now you just need to update. There is a guide to that on the way 😊
One you have updated you can, if you wish, change your product code back again by repeating this process and writing the old code.