I was waiting for the user to respond to me before I reply. He was making a generalized statement which is misleading. ANyway here is my understanding . First and foremost I am not an expert in such stuffs - this is based on my experience flashing the first Galaxy S and Galaxy Tab and present Galaxy S II.

PIT stands for PARTITION INFORMATION TABLE. The pit file basically tells Odin how to divide the partitions (for formating) and also where certain components ( PDA, PHONE, CSC ) to go when flashing them individually. PIT understanding is very crucial when you wish to flash roms from samfirmware.com , one place I always discourage new users from attempting as it is a trap to bricking a phone if you do not understand what you are doing

Cooked roms take cares of PIT ; you rarely see cooked roms asking you to choose PIT during flash thro Odin. Most cook roms, the developer has built in his rom the PIT instructions

For example, in the samfirmware.com Galaxy S site, you can even see different types of PIT listed and a warning that you choose the right PIT file. In its SGS II site, If you look at samfirmware.com - there is a default PIT file you can download at the top box just above the list of firmwares for different regions. If you download any of these official roms, you will see some roms comes with a PIT file and some does not. You asked a very good question, why is the PIT included if is of no use ?
My advise is simply this : If you see a PIT included in your rom, choose it during flashing as most probably the PIT is a changed version from default. You can only use this PIT to flash with the rom that comes with it. You cannot take this PIT and used it to flash another rom - this will brick your phone. When you use a wrong PIT - you have 2 possible scenarios :
- failed flash and phone cannot boot
- flash OK but the whole internal SD is formatted and cannot be detected at all by phone ( my experience with the Tab)

If the rom downloaded does not supplied a PIT file - than you just flash it without it or you choose the default PIT

As the PIT name implies, using PIT basically repartition /reformat your whole internal SD - once you select PIT, you will see repartition is auto selected. All your data in the internal SD will be wipe clean

You can choose NOT to select the PIT during flashing if you wish to have your internal SD intact. I cannot say whether you will have a successful flash. If is successful it just means your present rom PIT is similar to the rom you have downloaded. If is unsuccessful, just flash it again and select PIT

Read this post if you wish to know more. The writer similarly points out about the false/wrong understanding of many users about using PIT
http://forum.xda-developers.com/showthread.php?t=999097

If you check repartition - your internal sd ( all of it the full 16 GB) will be repartition /formatted and all your apps/ data gone. You select repartition if you wish to start with a clean internal SD card. You need a PIT file to do this unless is already builtin the PDA file

Rom files ( depending on the rom developer or the source ) are usually 2 types. After you have extract the zip file :

1. One TAR file : No need select PIT as is builtin - flash it as PDA
2. Minimum 3 separate files : Recommended to select PIT but again sometimes the rom developer will advise not necessary

there is no one fast rule - that's why I always say please read the rom features that you wish to flash

If you're on a rooted SGS2, boot into CWM and clear battery stats

Yaaaaah .. having a Brand new baby S2 in my hand now ..( bought it from samsung lowyat ... 2nd floor one laaahh ))

.. something very strange ... from turning ON till now .. cannot find chinese input on my set ....!!!

is this normal ... pls pls comment ..and show me how to deal with chinese input ...!!!

kam sia kam sia

The official stock rom latest 2.3.4 is very good. I normally do not say good stuffs about stock rom but this is indeed exceptional. Have dump those cook versions based on it,  villian, angeloM and litening. Most impressive battery life i rough estimate twice better than the cook roms
refer page 1 post#4 for more info

+1. Seems to be doing good for official ROM

just got this phone , is it wrong to root it on first usage 
moving from Symbian to this give me a major headache to begin with lol

Anybdy pls advice..

uncle benny, i just got my samsung and i flash to litepro rom v2.1.
i want to ask how to get back samsung TouchWiz, because i thought i already backup TouchWiz with titanium backup, but titanium backup only backup the data  not the app. so how i can get back my TouchWiz without reflash the phone? thank you

Im also trying to get back to touchwiz, coz my ADWlauncher seems buggy.. clear data for both apps, but cant reselect launcher wor..