Behringer PMH880S or PMX880S. I have seen them listed both ways.
http://www.behringer.com/PMH880S/index.cfm?lang=ENG

Whatever you get, you will want two speakers so you can be in stereo if you are using a PSR3000. The is a big difference in sound.

I bought my JBL 10G2's off ebay for $550 for both shipped. At the time I had never heard them, but figured if I didn't like them I could easily resell them on ebay.

Scott