Potential on the inside of a hollow insulating sphere

[valarking]

Homework Statement

We have a hollow insulating spherical shell of inner radius a and outer radius b. While it can be treated as a point for r > b, find the electric potential on the inner surface of the shell.

Homework Equations

$$\phi = k_e\frac{q}{r}$$

The Attempt at a Solution

My best idea is that I'm going to need to set up a triple integral. If this was from any point in the center it would be trivial, but it's a little harder from the inner surface. Any suggestions on where to start with this integral?

 

[Delphi51]

You'll need to know the charge on the shell and how it is distributed.
If uniformly, you should be able to get it with Gauss' law.