No sound from internal speakers on a Macbook?
Given that you changed OS's -- to the linux partition -- and still had the same problem, it sounds like a hardware problem.

If you did damage the hardware, don't worry -- you're not completely screwed.  This may be the best excuse to upgrade your audio hardware with an external sound card.

Creative has some great ones that I have used along with Adobe Audition.  However most of them are PC only... but in their professional brand (E-MU), they have some great ones for mac.

Creative's professional brand, E-MU is what I currently use.
Details here:


http://us.store.creative.com/0404-USB-2.0/M/B000IXNE3E.htm


Amazon link here:


http://www.amazon.com/Creative-Professional-0404-USB-2-0/dp/B000IXNE3E/ref=sr_1_1?ie=UTF8&amp;s=electronics&amp;qid=1295028320&amp;sr=8-1