While this method is meant for the Samsung Captivate it can also be used for all Galaxy S devices like the Vibrant and Fascinate. The Captivate is an older Android phone but still very popular. The Samsung Captivate is an AT&T phone but also easily SIM unlocked to work on other carriers like T-Mobile. The first step is to root the device and here it is.
Put you Captivate in USB Debugging Mode (Settings -> Applications -> Development)
Plug your Captivate into your PC via USB
Open SuperOneClick (wherever you just extracted it)
Click the “Root” button
When asking if you want BusyBox say Yes
When completed unplug your Phone and Reboot it
Congrats you now have root access on your Captivate!
If you want to test your Super User rights download Titanium Backup or any other app that requires root access and open it. You should get a superuser access window to accept and your good to go. As always follow these instructions at your own risk we are not responsible for its use.