According the the web page below, tan δ is the "dissipation factor" and in order to calculate the ESR you need to multiply it by the reactance value in ohms
reactance = 1/2πfC **broken link removed**
The esr for an average 10uF capacitor should be less than 2 ohms. (ESR is usually measured at 100Khz)
ESR is just the real part of the complex impedance WHICH IS A FUNCTION OF FREQUENCY. As such, no single value will do. To actually see it you should try to get your hands on a network analyzer. If you can't afford one maybe a friend will let you borrow one -- LOL.
Ponder the following. There is a frequency at which the complex impedance of a capacitor has no imaginary part and it looks like a pure resistance.
Even stranger. There is a frequency at which the capacitor behaves like an inductor. It's complex impedance has a positive imaginary part.