1. open your Captivate phone that's running the leak Android 2.3.4 I897UCKH3, and go to android market then download superuser and install it on your phone, make sure that you have done this step.
2. Go to download StocKH3 kernel with Clockwork Recovery from this guy or download here to make sure you have the right one.
3. Do you have Odin3 1.81? if not, download here if you already have then skip this step
4. once you downloaded everything and installed superuser, go to download su-2.3.2-efgh-bin-signed.zip for gingerbread and here a link
5. Now turn off your phone and open odin3 1.81 as administrator, then connect your phone into usb cable while you'are connecting press the volume up and down together to get into download mode (you can do another way to get into download mode it doesn't matter).
6. make sure that your phone connected to computer, you will see the yellow on the box, when you connected.
7. now put put the boog_kh3_kernel3.tar into the PDA section, then click on Start button and wait until you finished and your phone will reboot.
8. go to upload file u-2.3.2-efgh-bin-signed.zip into your micro SDCard, or your internal storage. then reboot into recovery mode, the best way to do this is "adb reboot recovery" you will see Clockwork Recovery mode
9. Now, Go to select Install zip from sdcard >> toggle signature verification >>> Choose zip from sdcard.
10. then go to select one the one you've uploaded on your sdcard or wherever you uploaded to (u-2.3.2-efgh-bin-signed.zip). then select yes to install it.
after you finished install u-2.3.2-efgh-bin-signed.zip from the recovery mode, reboot your phone and you are now rooted.
have a good luck, it worked as well. sorry about my english also.