I want to get new external speakers for my pb. i found these that i think will be good. http://www.logitech.com/index.cfm/products/details/US/EN,CRID=2,CONTENTID=9486 my brother has the "older" ones for his G5. Of couse he hooked them up using the optical. Since there is no optical on my pb how can i hook them up. I could use analog, but it won't sound as great. Is there a way to get optical for my pb or another way to hook these up?