File formats on external hard drives

Hi, i have had my 13" MacBook Pro since xmas time now and it is great, i recently purchased a 250GB Iomega portable external hard drive, i was told to format the drive to 'Mac OS Extended (journaled)' as this would apparently makes the hard drive quicker and easier to write and read too, however, after doing this i know have realised that i want to plug my external hard drive into my Xbox 360 and PlayStation 3, and as it is now in the Mac format, neither of the devices can recognise the Drive, so what i want to do is put the hard drive back to its factory state (according to the drive booklet was NTFS which i can apparently use for mac and windows and my ps3 and xbox) i also need to be able to use the hard drive at school when transferring data from my Macbook to the school windows XP PC's, can someone please tell me how to format the drive so i can use it for all of these things?

any help would be appreciated,

Thanks, David

To quote Bobtomay on the thread directly below this one at present!

To enable MAC OS to read NTFS.
"I prefer Paragon's NTFS for Mac which also provides software for Windows to read and write to HFS
There is also NTFS-3G
And there is also a way to enable 10.6 to write to NTFS - although not sure what limitations it may have - how to available here. I have not tried this either as all my NTFS drives are accessed via the network."