What is the time constant of this RL circuit? quick 10 points here

Consider the RL circuit in the diagram below with the following component values.
R = 117 ohms
L = 328 millihenries

and Vs undergoes a step change at t=0

Vs(t) = 0 volts for t<0
Vs(t) = 6 volts for t>0

What is the time constant in milliseconds?

A link to the diagram can be found here: http://imageshack.us/photo/my-images/809/screenshot20110516at124.png/

Thanks a lot, working out would be a bonus too.
I have other similar questions too. Quick 10 points.

The time constant in all RL circuits is simply L/R.

In this case:

L/R = 0.328 / 117 = 2.8 milliseconds