Sprint and Samsung have finally decided to grace Epic 4G with Gingerbread update. The Android 2.3 update just became official and will be available over the air, you r smartphone will get the notification and you just have to follow the on-screen instructions.
You can also manually trigger the update by going to Menu > Settings > About phone > System updates >Update Android.
Sprint Epic 4G Gingerbread update changelog:
Upgrade of the Google OS from Froyo to Gingerbread (Android 2.3)
Audible Sprint AIRAVE™ notifications when answering call
SMS messages sent without area code
PRL and Profile update
EAS (Exchange Activesync) email displaying HTML
Bluetooth headset sound improvements
Fully visible date on device lock screen
As the update is being rolled out in phases, you device might take up to ten days to receive the update notification.