They're good for bleeps and bloops but that's about it. Same with every other laptop. Even the PC laptops that come with brand name "audio systems" still sound like crap as far as I'm concerned.
You just can't transmit a lot of sound any distance with such small drivers. If you need good portable sound, pack some headphones. I got a decent pair of sony ear buds for $9.99 years ago and they work fine.
As for the Mic, there are several good USB mics to choose from. The ibook does have a built-in mic in the screen but, like the speakers, it's not the greatest. It'll get the job done in a pinch but, if you need high quality, you'll have to pack your own input device.