Where can I get Ninja Noise?

[Photolistic]

Also will it work for my PS 8?

[Detrimental]

Some old kung fu movies probably good audio clips of ninjas screaming, you could try starting there.

Google ;)
http://www.picturecode.com/

[Scottes]

Detrimental has the link correct, and Yes it will work with PS8. You can also get a cheaper stand-alone version, but the Photoshop Plugin version is *highly* recommended since you can then use things like masks to protect edges. And all the rest of PS's power.