[CentOS] How do I identify my hardware?

I'm a little new to CentOS and very rusty on Linux in general (it's been 7 years since I worked on a Linux kernel), so this may seem like a dumb question.

I have two issues with my machine - sound and video. My sound card is not recognized at all (I think it's on the mobo, but I'm not sure how to identify it), and I have an ATI dual video card with two screens, but both show the same output, so I'm guessing that my CentOS does not know what it is, either (they show up as unidentified in the config file).

I'm running 2.6.9-42.0.3ELsmp and can't upgrade to a newer kernel for the time being.

Any suggestions?

Thanks.