Heya Gotrek,
The POT should have an ink stamp, or embossment which states a number then K, M or ohms, or the Omega symbol, or R. This will be the value in Kilohms (K), Megohms (M), or ohms (Ohms or Omega symbol or R). For instance, 100K means 100,000 ohms or 100 kilohms. 100R means 100 ohms. 100 omega symbol means 100 ohms, 100 ohms means 100 ohms Etc.
If you can't find the stamp, or embossment, and you have access to a multimeter, you can touch one mulitmeter probe/clip to one of the outside terminals, and touch the other multimeter probe/clip to the opposite outside terminal. Make sure your multimeter is set to measure resistance. This will give you a reading, depending on what setting of resistance that you are measuring.
I haven't run across any pots that have a color coding system that demonstrates the value of the pot. If there is such a thing, I assume that the color code system for resistors is used (4 stripes, one being the tolerance). You can find the resistor color codes on google.com, or I can email you an excel spreadsheet which will calculate the value, given the colors.
I hope this answers your question.