You can use Odin to flash cwm 2.5.x. Get the red version found
here. Use the odin one if you don't have clockwork already.
Odin can be found here.
Download the drivers to your computer (
here
From Droid X:
4.) If your phone is plugged into your computer, unplug it now
5.) If your phone is not powered down, power it down now.
6.) Remove battery from phone.
7.) Launch ODIN on PC.
8.) Plug USB cable into phone.
9.) Plug your Fascinate into the PC via USB cable.
10.) Press and hold the volume-down key until you see a gigantic yellow triangle and your phone will be in download mode
11.) Click on the PDA button in ODIN
12.) Choose the cwm Odin from above.
When finished, remove usb, insert battery. Hold the volume - and volume + and hold power. Samsung will flash twice. Right after the second time let go of the buttons. You should now boot into clockwork within a few seconds. Use the volume key to navigate inside cwm, the power key to select, and the menu key to go back.