If I upgrade using network update

Will I go from firmware 1.5 to the latest which sounds like 2.6 or will I just go up to 2.0?

I am affraid to lose the games I do have currently on my PSP, really I am hoping the come out with an emulator that will allow you to play the new games that are coming out. But I am guessing if I update and have 2.0 firmware I will be able to play some of the new games with a different emu. Currently I am using fastloader, but can't play prince of persia, megaman X, street fighter alpha 3, king kong etc.

What is the best way to go?

Version 1.5 is the only version that will play ISOs off the memory stick using a loader.

If you use network update you will have versi 2.6 and will NOT be able to play ISOs or downgrade.

2.00 games can be played on the 1.5 now using MPH's loader. Games like socom and GTA work. There are more, i just cant remember them.

If you don't have a game with a 2.0 update, you can always download it..

I dowloaded the MPH, but it is really hard to figure out, how to set it up. Where do I put my games? In the same Iso folder. Also I don't know anything about changing files?

what firmware version do you have now?

still have 1.5 with fastloader as my emu

You don't need fastloader if you have 1.5.

OK that may be but it works just the same. But how can I use the MPH

Do you want to use MPH on your 1.5 so that you can use the 2.5 web-browser on there? If so, have you downloaded it yet?

Actually, if you have 1.5 and you test connection, you infact will update, but you would be stupid enough not to because before you actually update, it will ask you:
This will update your PSP FIrmware to 2.0 or 2.01 or 2.05 or 2.06, do you wish to Continue?
Unless you want to go on the internet, you should click continue of what eevr but if you dont want another firmware version on your psp, just cancel it and dont even try going into network update.