I order a new web server , windows 2008, it has 2 hard drives which has software RAID1. I need to split hard drive to 3 partition, how can I do this?
Windows Server converts your disks to dynamic disks when you use software RAID, so most oldschool partition managers (pqmagic, fdisk etc) will be useless.
The quickest way to do it would be to right-click on the partition in Disk Management (from the Server Manager console > Storage > Disk Management) and go Shrink Volume. Once it's been shrunk to have a bunch of un-allocated space, you can just create new, smaller partitions.