I've been wondering about this too and there seems to not be any open source, or free shockwave plugisn for mozilla or opera browsers in linux. I did find a petition
hxxp://www.petitiononline.com/linuxswp/petition.html
But as we all know, things that are cost $$ are free to some. That i will not mention since it is not allowed in the forum. Just mentioned that some ppl get things for free.
flash is the only pluggin i have working in firefox from macromedia.