Updating ps3 via internet
Sony offers three different ways to update your PSP's firmware, so you can choose the one that works best for your internet connection and equipment.
i know this for a fact as i didn't game online with my ps3 for about 6 months and everytime i popped a new game in that required an updated firmware it would install it from the firmware required for the game is bundled with the game.
), and then put it on your PS3, but you will still need to update the PS3 before the PSN account can be put on the PS3 (choose Use an Existing Account instead of Create a New Account if you do it this way when setting up the PS3).
Update the PS3, then create or add your PSN account, this is the only way to do it.
It can be a good strategy, though, if you only want to bother updating when you have to to run the games you own.
If you don't have a wireless internet connection or never use the internet on your PSP, you can also download PSP firmware updates to your computer and update from there.