Help with PSP question

I'm Interested in buying a PSP but I have a fast question.
Can I downgrade any ver now? or only up to 2.0?
is there a risk to downgrading? or can it be done many times?
Do they have all emus for all versions?

I'm interested in picking one up, since I saw that theres a program to play AVI files on it now..

Thanks for the info.

www.pspcrazy.com

www.pspupdates.com

Everything you need to know about PSP emulation.

I haven't really kept up with the homebrew scene ever since I upgraded to 2.6 (haven't looked back), but here's what I know.

You can only downgrade from firmware 2.00, anything above that isn't possible as of right now.

Downgrading is pretty safe last I heard. I did it a couple of times myself and I didn't run into any problems.

Some emus/programs won't work on the 2.00 loaders, and even less will work on 2.00+ from what I know. 1.50 is the only one that'll easily let you run anything you put on it.