Update: I made this very easy tutorial which has like 100% success guaranteed.
WARNING: MAKE SURE YOU HAVE THE ORIGINAL CER24 and CER27 FOR THIS METHOD!
1- Download this:
http://www.mediafire.com/download.php?b8f65nbps16w3e4
2- Extract the files to your desktop, copy all files except F***psnv0.5.exe to the root of any usb device.
3- Connect the usb device to your PS3, and install all 3 packages: dev_blind, Awesome File Manager signed, and 3.56 version spoofer.
4- Open 3.56 version spoofer, click on X to install the spoofer(wait for 5 seconds) then it will say that it is completed.
5- Don't quit the game, turn off the ps3 by pressing the On/Off normally.
6- Turn on the ps3, go to System Settings then to System Information, then make sure that your system software is Version 3.56. You spoofed your ps3!
7- Open Dev_blind, it will say the creator of it, then it will ask to Mount dev_blind, Click on yes! then O and you'll be back in XMB.
8- Open Comgenie's Awesome File Manager(make sure your usb device is still plugged in).
9- Press the Select button to go to Advanced Mode. On the left side, go to dev_blind\data\ delete CER24.cer, by pressing the square button then start.
10- Go to the right side by pressing the Right button, then to dev_usb00x, highlight CER24.cer(the one you copied earlier) and copy it to the left side by pressing the O button then start.(make sure CER24.cer is on the left side!)
11- Turn off the ps3 by pressing the On/Off switch, the turn it on.
12- On your computer(where you're runnung F***PSN 0.5), go to Start the Run the type cmd, the type ipconfig and press enter.
13- You will have 3 IPs, the first should be IP address. Memorize that number.
14- Go to Network Settings, then Internet Connection Settings, custom, wireless/wired.
15- Here is the most important part: PRIMARY DNS: THE IP ADDRESS IN THE CMD I TOLD YOU TO MEMORIZE EARLIER.
SECONDARY DNS: 8.8.8.8(always works)
16- Save the settings, now on your pc open f***psn-v0.5.exe(if it gives you a security alert then just click on Unblock)
17- Keep f***psn-v0.5.exe open on your pc and Log In on your PS3!!!