Hello mindnever and welcome to this forum!
First of all - I'd like to know why you would like to format your MB? If it's brand-new it's ready to be used. You just need to create your desired shares, and you can map them on your Windows PC.
You'll have to keep in mind that the MB has several partitions (4 in a MBWE 1TB) with built-in RAID on top.
[root@Jupiter ~]# fdisk -l
Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 5 248 1959930 fd Linux raid autodetect
/dev/sda2 249 280 257040 fd Linux raid autodetect
/dev/sda3 281 403 987997+ fd Linux raid autodetect
/dev/sda4 404 121601 973522935 fd Linux raid autodetect
I'm not sure about the RAID settings, but in the end you get a system partition (which holds the operating system that makes the device work) and a data partition where all your data goes. As far as I know these partitions use XFS filesystem http://en.wikipedia.org/wiki/XFS. If you realy want to format your data partition, you would have to log in through ssh, probably install Optware (I recommend using frater's script) and run a mkfs.xfs command with the correct parameters to recreate (format) your data filesystem.
Please note that if you make mistakes or if the parameters to mkfs are somehow incorrect, your might brick your MB! So, I wouldn't recommend doing a format unless you are sure this is what you want…
If the MBWE is not brand new, you can use this post to try to get it back to factory settings: http://mybookworld.wikidot.com/forum/t-171834/my-book-world-edition-white-unbrick-guide