Big Event need advice (430EX and light metering)

Hey Guys,
I have a big event coming up this Friday and I am pretty clueless in flash photography. I need to get a shot of a VIP in front of our company logo. The room is 20 x 20 with 8ft white ceilings and dark blue walls. The tools I have available to me are:

Canon 350D
Canon Speedlite 430EX
LumiQuest SoftBox
LumiQuest 80/20

Lenses:
Canon 50mm 1.8
Sigma 35mm 1.4
Tamron 28-75 2.8

I am thinking of using the Tamron and just bouncing bare flash off the ceiliing. The following are my questions:

1. Do I meter the ambient light first?
2. Should I set the ISO to be very low?
3. I was thinking of f8 as the proper AV for a portrait?

Thanks for the help!

I would use the Tamron, 430EX in ETTL pointed towards the ceiling (but slightly forward) with a white bounce card so you get some direct light.

For the camera you have two choice:
- Camera in manual, 1/100th, ISO400, F5.6-F8 or so - that way you're using the flash mainly but perhaps getting a little ambient light in.
- Camera in Av, F5.6-F8, ISO set so you get a shutter speed of 1/100th or so. Diffuser of some kind on flash, flash pointed directly at person, FEC set to -1 (ie fill flash).

You REALLY need to practice before you take the real shot - try both of these, see how they look on a full size monitor, then tweak them as you need to

Not sure about the lens as I don't know how much of this VIP you want and the size of the company logo. But, as I read your post I felt myself reaching for my LumiQuest 80/20.

Thanks Tim/Jon! I brought my camera to work today to do a test shoot with our receptionist haha. I will use your advice and see what I can get.