Hi
There are many ways around this problem.
You can get a cheap PCI sound card for about $15.
PCI soundcards usally have a 15pin port in them.

Secondly...there is a conversion lead/adaptor
Take a look below

ANALOGE:
http://www.maplin.co.uk/Module.aspx?...ID=4&doy=23m10

DIGITAL:
http://www.maplin.co.uk/Module.aspx?...ID=4&doy=23m10

I use AFP, but not the game controller, im not sure which one it is.
I hope this helps

Cheers
Volkan