I have the same laptop and the same problem, and am using ubuntu 6.10 (kernel 2.6.17-11 I believe). I found that when I compiled a newer kernel (2.6.20), the headphones worked fine (but then the speakers didnt!). Compiling the kernel yourself might be a little difficult if you are new to linux, and you might find that while you fix one problem, you might create a new one (my wireless stopped working). My suggestion would be to install Fiesty when it comes out next week

. Hopefully it will resolve the above issues

.