You could use a script to get the information from WMI (from technet):
...determine the IP address of a computer?
Use the Win32_NetworkAdapterConfiguration class and check the value of the IPAddress property. This is returned as an array, so use a For-Each loop to get the value.
strComputer = "."
Set objWMIService = GetObject( _
"winmgmts:\\" & strComputer & "\root\cimv2")
Set IPConfigSet = objWMIService.ExecQuery _
("Select IPAddress from Win32_NetworkAdapterConfiguration ")
For Each IPConfig in IPConfigSet
If Not IsNull(IPConfig.IPAddress) Then
For i=LBound(IPConfig.IPAddress) _
Sadly that's code for the local machine, and you'd need to tweak it according to this article to connect to the remote WMI.
It might just be easier to have each machine write its IP address to a text file on a network share when it starts up.
Or you could query the DHCP server directly for the information (if it's MS, http://serverfault.com/questions/110864/can-i-query-dhcp-server-for-getting-mapping-of-mac-to-ip-address-i-have-admin-ri should work)