Ferrite Bead: How much impedance do I need?
You need to know the behaviour of the noise current: knowing its frequency and its amplitude, you should be able to compute the voltage drop across the ferrite bead at that frequency. Getting to the answer, the impedance should be such that the noise voltage drop on the pin of your IC (at the noise frequency) is much less than the voltage drop at the working frequency (DC, since you're interested in the power supply pin).