The usual suspects have the play-by-play, but the big announcements on the first day are Leopard and the Mac Pro. Some serious workstation-class performance on the Mac Pro, with quad-core (2xDual Core Xeons) processing, tons of ram, full 64-bit, and the same design case as the current workstation box.
Nothing on the audio side yet, I’m sure that will come later in the week. No sense busting your whole nut in the first two hours.
On a side note, VMWare announced they are supporting OSX with their line of virtualization products. I’m a big fan of VMWare, so that’s a nice thing to hear, particularly if Apple starts making some nice servers running OSX for hosting VMs.