Here is a link to a dark taken under the same conditions as yours using my ATIK 428. This camera is identical except for using a smaller version of the same CCD so should be a direct comparison.
If you have ISIS, it includes a nice feature which you can use to calculate the gain, and noise figures described here
These warm pixels are not specifically measured using this technique though. To get the dark current figures quoted by ATIK and measured by Christian Buil, you have to chose a measured area free of warm pixels.