I could really use some help with this.

I ahve no interest in playing old games, however i want to download iso images of games and play them from my memory stick.

I'm on firmware 2.6. From what i understand i can use umd emulator onc i have my iso's but will this work with my 2.6 version.

I also would liek to know if i can play the iso's from my iBook into the psp as my memory card is quite small..

Some detailed help would be great

To play ISOs, you firstly need to downgrade your firmware from 2.6 to 1.5.
Then you need to install DevHook:
http://www.psp-hacks.com/forums/post-315470.html#p315470
Then to play from your iBook you need a DevHook Mod that supports USB loading, I recommend Wedge's VSHEX DLX:
http://forums.maxconsole.net/showthread.php?t=26673
Then you need something like PSPHost runnig on your PC (or anything with USBHOSTFS).

Is it possible to downgrade from 2.6 to 1.5?

Also i have no access to a PC i'll be doing it through a mac.

There's so much confusion about how this is done on the internet. One minute i'm led to believe it can be done and the other minute it's impossible.

I'm new to it but and could really do with some detailed way of going about it....

Ta very much

It IS possible to downgrade from 2.6 to 1.5 IF you don't have a PSP with a TA-082 motherboard.
The method requires you also to have an original, unpatched, GTA:LCS UMD. (I used this on my PSP)

It is also now possible to downgrade from 2.71 to 1.5, again only if you don't have a PSP with a TA-082 motherboard.
This method does not require GTA:LCS, but can be slightly frustrating as it could take a few tries before it runs (it took about 8 tries on my friend's 2.71 PSP)

So if you want to downgrade to 1.5, this should be the easiest way:
1. Check that you don't have a TA-082; the picture here shows it clearly:
http://www.maxconsole.net/content_img/ta82spot.jpg
If you have a TA-082, bad luck there's no downgrader at the moment.
2. If you don't have a TA-082, upgrade to 2.71:
http://www.psp-hacks.com/file/525
3. Downgrade from 2.71 to 1.5:
http://www.psp-spot.com/forums/index.php?a...ls&f_id=725

I've managed to downgrade to 1.5, all i need now is a tutorial on how to run iso games from my laptop through my psp opposed to the memory card. I could really do with some kind of step by step guide to do this. The only problem is that i'm using a MAC ;(

I've replied in your other thread about running games from USB:
http://www.psp-spot.com/forums/index.php?showtopic=27708
Since you've downgraded successfully (well done!), I think we can let this thread die now.