Serendipity! I was just thinking about trading in the old Samsung work standby for a new iPhone. Although all the other devices in my ecosystem are Android, I figured adding iOS back to the mix would mean changing how I do things again.
Also, all my Android devices run CyanogenMod so I wanted to keep it homogeneous.
First things first: Get rid of whatever rom I had on there before.
This will take you back to stock. You need the Odin from there plus the stock .zip file. See the thread for the linkages. Let me know if they disappear, I can link them here.
Next, you need some root lovin. Go to this thread for a one click method, coming from the stock you just flashed above. This also installs the latest/best ClockworkMod (CWM) for the Epic. One Click Root for Epic 4g
Ok, so that is all sweet, you have your CWM installed, so go download the files. Follow the wiki and then done. Cyanogenmod Wiki: Epic 4g
And done. Questions?