I like to use a conversion chart such as this:
http://antiqueradio.org/art/recap13.jpg
I have a better one printed out, but can't remember where I found it on the net.
If you can read resistor color code, the capacitance is the resistor color code of those 'K' numbers on modern yellow replacements. For example a bumble bee with the first three bands YEL PUR ORG decodes to 473 which can be replaced by a modern cap with value of 473K(this is 47*10^3 thousand pico farads or .047uF)