On the Windows server where iSCSI will be installed:

(This is for Windows 2003. Note that you must have Administrator rights to install this.)

Go to the MicroSoft Download Center and download the current version of iSCSI initiator (free download). http://www.microsoft.com/downloads (search for iscsi initiator)
Download the correct version for your server - there are versions for 32 and 64 bit machines.

Run the installer.

A selection box appears with 3 options:
Initiator Service
Software Initiator
Microsoft MPIO Support for ISCSI

Check and install all 3.

When done you need to reboot.

After rebooting you'll find a Microsoft iSCSI Initiator icon on your desktop (and in Start; Programs; Microsoft iSCSI Initiator).

Double click the icon. Near the top of the properties panel displayed, there is a line that says:
'Initiator Node Name:' and something like iqn.1991-05.com.microsoft:xxx' (where xxx is your server name)
The above name must be provided to the DoIT Storage team (storage@doit.wisc.edu) to configure your storage.

Click the Discovery tab.
Click the Add button. Enter the DNS name of the storage as provided by DoIT (normally xxx.doit.wisc.edu). Leave the port at the default value of 3260. Click OK.
If the discovery fails, make sure your firewall is not blocking access.

Click the Targets tab and you should see a target named iqn.1992-08.com.netapp:sn.xxxxx
Click the Log On button.

A pop up window appears with options to 'Automatically Restore this Connection when the system boots.' and 'Enable Multi-Path'. Normally check both of these.

The Target screen should now show a status of Connected.
Click OK to end the iSCSI initiator program.

Open Computer Management (right click on My Computer and select Manage).
Click Disk Management.
Click Action; Rescan Disks.
A new disk of the size you requested should be shown. Initialize, format using Quick Format, and begin using like any local disk.