mstechca said:How do I calculate the capacitor's inductance?
You don't, there's no reason to want to?.
wait a sec... you say that a few uF's make too much inductance. Why do you suggest adding 100uF to 1000uF?
As Audioguru said, you want two capacitors across the supply, a decent size electrolytic (which will decouple low frequencies, and greatly improve battery life), and a much smaller capacitor (like a 1000pF) to decouple at high frequencies.