Possibly... but if the rom you choose is prerooted, you shouldn't have to root first. What you do need to do, is download the program Odin, and get the update.zip containing the version of clockworkmod that you need to flash the rom itself, andthe .tar.md5 containing the recovery kernel. You also need the .tar.md5 file that contains the kernel and modem for the rom you choose.
the step by step is this:
1. download the version of cwm you will need (most likely 2.5. It should be located in the same thread as the rom that you are getting, and the rom itself (it will also be zip file)
2. hook your phone to your computer, and place it in mass storage. Then drag that cwm file (it will be labeled update.zip), and the rom file onto the root of your sd card (not in any folders).
3. turn off mass storage, unplug your phone, and download the drivers for your phone from samsung website, then install them, following the instructions.
4. activate usb debugging by going to settings>applications>development. Note, your phone has to be unplugged from the computer to do this.
NANDROID BACKUP.... DO IT
launch Odin, and place the tar file containing the cwm kernel in the PDA section of the program, place your phone into download mode by removing the battery and holding the volume down button while plugging it in. Then wait for ODIN to connect (it will show a colored box with 'COM' and a couple of numbers). Then hit start. wait until it passes, then resets (This should only take a few minutes). Unplug your phone, reinstall the battery and reboot into recovery, using 3 finger method (power, vol up and vol down at the same time).
using the vol down, and menu softkey (it won't be lit up) select 'apply sdcard:update.zip'
go to backup and restore, using the vol down and the power key to select
select 'backup' with the power key. sit back and wait a few. It will back up your current rom to your SD card... As long as you can get into recovery, you can apply this and get your phone back if you ever have a soft brick, or you need to restore it to factory for warranty.
Now, go ahead and go back to the main cwm menu, and select 'reboot phone now.'
5. remove your battery, then plug your phone in while holding the volume down and power button.
6. fire up odin, and wait for it to connect to your phone... you will know it's connected when you get a yellow box with the word 'com' and a couple of numbers.
7. place the .tar.md5 file into the PDA section of your phone. MAKE SURE IT IS NOT IN THE PHONE SECTION!!, then hit start. It shouldn't take more than a few minutes. after you get a 'reset' in odin, unplug your phone, and place the battery back in.
8. reboot into recovery, by holding down the volume up and down and power button at the same time (called the 3 finger method).
9. once there, use the volume down button and the menu key (it won't be lit up, just hit where it should be) to select 'apply sdcard:update.zip'. This will launch you into the clockworkmod (cwm) that you downloaded.
10. using the volume rocker, and power button to select, go to 'install zip from sd card" and select it.
11. go to 'choose zip from sdcard" and select it... it will give you a list of them. Choose the one that is the rom. scroll down to yes. and select it. Give it a minute or so, at this point... it's installing a completely new OS.
12. back up to the main cwm menu again, and go to advanced. There, select 'wipe dalvic cache. This will wipe all the data from your apps, and the settings that allow them to interact with your ROM. It won't wipe the actual apps, but it is neccessary to avoid glitches and force closes.
13. go back to 'reboot system now, and select it... It will hang up on verizon splash screen for a while... go get coffee, and a smoke. It's doing the final install on the rom... 5-15 minutes, depending on the size of the rom...
If the rom you downloaded is prerooted, you won't need to bother with it. If not, then you can use super one click, to do it... but all of the ones I've found for our phone are prerooted.
and the obligatory disclaimer:
I'm not responsible for what happens to your phone. If you have any questions, or I didn't make something clear, feel free to ask. I have no problems answering them, and I'm not going to give you a lecture about doing research before I do. this method does work. I've done it on 3 different roms, now.