Those guided really helped me out
I spent ages reading up different things so when I finally went and did it, I didn't face any problems!
1. Root, obviously :P I personally didn't use the latest edition of SuperOneClick (at the time) on the website, but the file the dev posted on his XDA Thread.
2. Don't use ROM Manager or any other 'one click' kind of recovery for this phone. You need to download a custom recovery file and update file (links above, thanks Krylon) and go into CWM Recovery through the official Samsung Recovery through reinstalling the custom update file. This is the only way to access Orange CWM. Most custom ROMs come with the Red Voodoo CWM which is permanent in the sense that when you go into recovery, you should go into CWM (Red), instead of having to go through Samsung.
3. Orange CWM (and some say Red CWM as well) has some mounting issues. Always remember to check your mounts such that System, Data (well just to be safe, all of the items in the list) always say UNMOUNT. Basically when its mounted, means CWM has access to the partition. It says UNMOUNT because it is MOUNTED. I know thats a bit confusing, but think of it like this - there is a light switch that says ON so when you press it, turns the lights on but then the writing changes to OFF because you need to push the switch to turn it off. Erm .. hope that helps?! Lol.
4. Basically if your partitions are showing up as MOUNT, means you need to MOUNT them. Otherwise whatever changes you did won't apply! Instead of getting confused like I did, just make sure the screen says UNMOUNT SYSTEM and so forth for the rest of the items on the list.
5. Before installing a custom ROM, I always wiped x 3, before and after. Means after checking mounts, wipe data / dalvik, etc. 3 times. So for me, after checking mounts I would go to wipe date - yes - done 1; wipe data - yes - done 2; wipe data - yes - done 3. Followed by wipe dalvik and whatever else you want to wipe. Then I'd check mounts again (they usually get unmounted after a wipe .. well for me they always have anyway) before installing the ROM. Oh, sometimes I installed the ROM twice. Then I'd check mounts, wipe x 3, check mounts again before finally rebooting and letting it stand still for around 20 minutes or so. I don't really know if there is a logic or if doing it so many times makes a difference but I know some other people have done this and (other than wasting time) it doesn't really do any harm (someone correct me if I'm wrong) so why the hell not? I think the basic reasoning behind double / triple wiping and installing is to make sure that the changes are properly written as sometimes the system still retains old data.
6. Some people have SD card partitioning issues apparent. I can't remember why everyone went around partitioning in the first place (it must have been for some important reason, completely slipped my mind right now .. I personally did it to link my apps / data to SD card and save internal memory / space) but I personally used Gparted to partition my card on a computer (rather than CWM on the phone as I've heard people have issues with this) and never had a problem.
But I think thats it. I know there is a lot of information but its really worth having a look at the guide and other posts on that thread as that and the ROM thread (I personally use GOV 3.2) really had me prepare for any possible issue beforehand so I started off in a position where I could avoid them.