Many people don't know how to resize a Windows Server partition. This page lists some tutorials resizing partitions in Windows Server editions, including Server 2003/2008 and Small Business Server 2011/2008/2003.

Windows Server 2003

Windows Server 2008

Windows Small Business Server

Hardware RAID

VMware

Hope these guides helps you in a way.

It is not hard to resize a server drive, the most important for a server is data safety, so you'd better select a reliable partitioning utility, otherwise, it may cause data loss or system crash.