Here you can find the latest (25th of August 2011) stock Android gingerbread release for Samsung Captivate - i897.
It was not tested on i896/i9088 or i9010. If you tested it, please report back.
This package does not contain bootloaders so the risk of bricking your device is very limited (close to zero)
This is Android 2.3.4
Continuum Forum Thread Link
The zip contains the .tar.md5 that you need to use in ODIN. Don't forget to extract before trying to flash it.
Odin 1.83 (tested ODIN versions 1.82 and 1.83)
How to (semi-dummy proof)
1. Reboot in recovery (check this thread for hints) and perform factory reset by selecting the option circled in red and then confirming the selection.Navigation is done with volume keys.
After the reset is done, power off the device either from recovery (if option is present) or by pulling out the battery.
2. Reboot in Download mode (check this thread for hints)
3. Open ODIN
4. In ODIN click the PDA button
5. Select the extracted package
6. Click the START button in ODIN. It will flash the ROM and reboot by itself.
Note: you will need Samsung drivers for Galaxy S for following this guide. Easiest way to get them is to download and install Keis from here (make sure Kies is not running while using ODIN)
If you have them already then you're good to go.