There are many unsigned apps for the Nokia N8, if you really wish to download those applications then follow my guide below, please note that you need Windows OS for this to happen. You do need to have certain files to follow this guide, scroll down for some of them.
Please first download all the necessary files: Navifirm, Phoenix and the ones at the bottom of the post.
After acquiring Navifirm, download your Firmware to a folder called RM-596.
Open the file you have just downloaded with the Nokia Cooker then paste the installserver.exe that you have download into sys\bin, after that save the firmware.
You’ shall see that Nokia Cooker created a backup file.
Copy the RM-596, then look In the Phoenix directory for a folder called “products”, paste the copied file into the “products” folder, do no paste the UDA file downloaded from Nokia Cooker.
Then rename the BACKUP file to the original name.
After you have followed those steps then open Phoenix, as usual, search your phone, go to the “Flash Firmware” tab to select your firmware file.
Then click on refurbish. After the flashing process begins, an error should occur. Don’t press yes.
Then overwrite the original Backup UDA file with the hacked UDA file.
Now you can press yes in Phoenix, if everything went well, it means that you can install any application on your Nokia N8 device.