Nocturnal shooting/ Flash questions ?

Total newbie to using a flash, too be honest I almost never even use the on-camera flash. Looking at doing some nocturnal wildlife shooting and wondering if an external flash will make it easier or not. I will be doing fairly close range shooting but can't use the on-camera flash as when in darkness it strobes a bit. Do external flashes do this also to assist with focusing or is the focus assist beam some other kind of light/lighting.

I will be using the 350D/XT in close to total darkness so I can't use MF, and the animals will most likely be very skitish so there will be no 2nd chances. I was wondering if the Sigma DG500 super would be of any use for this kind of work. Any help, tips or info would be great thanks folks.

The AF beam from any external flash is good even if you don't use the flash. You can use a beamer thingy if the range isn't good enough.

The AF assist beam on external flashes are not pulsations of the flash like that of the built-in flash but rather separate red lights which emit a pattern of either vertical or horizontal lines.

What I thought, looks like I'll need to grab myself one. How bright is the red light in general.