Root Samsung Galaxy S

My 'guide' to flashing a custom rom and rooting is just a consolidation of stuff pulled from all over. I will provide references where appropriate and I hope it helps others.
Pros of doing this: more control over your phone, if Samsung do an Over The Air (OTA) update then it removes Optus from the loop
Cons: May void warranty, more control means greater potential to stuff it up

In this guide we will:
- Flash to official European Firmware I9000XWJG1 (aka JG1), then
- Flash a rooted custom rom based on JG1, Modaco's Custom Rom r2

Disclaimer: What you choose to do to your phone is up to you. All care is taken but no responsibility. The more you research this the better

1.) Sign up to Samsung Firmwares. This is not an official Samsung site, but they do store most official Samsung firmware releases.

2.) Once signed up, go back to the Samsung Firmwares website and download I9000XWJG1 (European rom) then scroll down and grab the Flash Program (Odin) and the .PIT file. Unzip the JG1 file.

3.) If you haven't installed Kies, make sure you have the drivers installed. 64 bit here. 32 bit here

4.) On your phone go to settings --> about phone --> USB Settings --> set to Mass Storage. Then go to Settings -> Applications --> Development --> Enable USB debugging mode. Plug your phone into the PC and make sure all the drivers load up

5.) Unplug phone. Switch it off. Remove microSD if you have one. Open Odin. Load .PIT file. Load the 3 separate firmware files: CODE file in PDA field; MODEM File in PHONE field; CSC file in CSC field. Pretty sure I used the CSC-I9000OXEJG1

6.) Your phone is still off. Boot into download mode by holding: Volume-down + Home key + Power. Plug the phone in and make sure all drivers load. Wait 30sec to be safe. Then click start.

7.) This has flashed a generic European firmware and removed all the Optus apps. You could replace JG1 with JG3 if you like, but the differences are minor. If all you wanted was a generic firmware you can stop here.

8.) Next we flash a rooted custom rom, Modaco's Custom Rom based on JG1 r2. You must be on JG1 to do this. If you are a Modaco member (worth the few dollars) you can use the 'kitchen' to 'bake' a rom with the components you want. If not you can download a prebake which includes all the default options here.

9.) Download the file and rename it to update.zip (ensure the extenstion is correct, NOT update.zip.zip). Download ADB (Android Developer Bridge) if you dont already have it here. ADB allows you to issue commands to the phone from the command prompt.

10.) Ensure USB Debugging mode is still on. Plug in the phone. On your PC open a command prompt 'cmd'. Change directory to where ADB has been copied. Issue the command 'adb devices' or 'adb-windows devices' to ensure ADB sees the phone. If it does, type 'adb reboot recovery' or 'adb-windows reboot recovery' to reboot into the recovery partition.

11.) On your phone you should now be in the recovery partition. Use volume keys to navigate, home button to select. Apply the update.zip (some error comes up, dont worry about it)

12.) The phone will take a while to start up, dont panic it is deodexing on the first boot. You are now running a rooted custom rom

References from XDA and Modaco. Any errors or omissions let me know, I will update the post.