It just occurred to me, that having the USB to
DMX adapter may not really solve the idea you have. You ant your sound and lights to be able to be cued simultaneously, so that would require either two pieces of software that can talk to eachother, one for lights and one for sound or one software to control them all. I have no knowledge of either of those exist.
So, I ask, do you already have a lighting
console and are you just trying to find something to use in it's place or are you starting from scratch? If you have a
console already an easier route to take may be
MIDI Show control. Most consoles these days support
MSC and if you use a program like SFX for your sound you can just like the sound computer and lighting
console via
MIDI.
Another option if your systems don't accept
MIDI would be
Rosco's "Keystroke" (
http://www.rosco.com/us/software/keystroke.asp). This device allows you to connect your lighting
console to a box that can effectively press a key on the keyboard of a computer. Thus if your sound software used F12 as the GO
button you can have Keystroke push F12 when you bring it's
channel up.
These options only are viable if you have a lighting
console. The other benefit to these options is that it keeps your lighting and sound systems separate so that if one goes down they both don't.