We are still waiting for the DROID Charge to get updated to Android 2.3.4. It was supposed to happen in August, but for now we will have to enjoy the leaked builds. Back in July update EP1H leaked, and now My Droid World brings version EP1W. You can flash this using the Samsung Internal Flash Utility or by using Odin.
Release notes: This is unofficial and a leak. Teamblackhat, Mydroidworld, and p3droid are not responsible for what you do to your phone. Installing this firmware will void your warranty and may cause harm to your device.
You will need 7z to uncompress these files. Download
Samsung Internal Flash Utility: Samsung PST - Download Now
If you don’t want to use the official flashing software you can use odin.
Odin 1.82: Download
You will need the Samsung drivers: Download