It is not out for the Captivate since no code has been given by Samsung for Froyo. There is a guy Gdanko at XDA working on an AOSP project where he was given code for the Vibrant and is trying to make it work.
The Cyanogen site has posts from some of the devs about only having gotten the hardware in early October. Apparently Samsung is doing things differently somewhere that is causing it to be Not Simple.
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