I’ve put a little command line batch utility to the output [1] which enables you to easily change your IP address from within the commandline in windows.
Tested on XP SP3.

Usage:
------
changeip.bat adapter static|dhcp [IP] [Gateway] [DNS]

Examples:
---------
Change Network adapter "LAN" to dhcp
changeip.bat "LAN" dhcp

Change Network adapter "LAN" to IP 192.168.0.1 (leave Gateway and DNS as is)
changeip.bat "LAN" static 192.168.0.1

Change Network adapter "LAN" to IP 192.168.0.1 (Gateway and DNS to none)
changeip.bat "LAN" static 192.168.0.1 none none

Change Network adapter "LAN" to IP 192.168.0.1 with gateway 192.168.0.2
and DNS 192.168.0.4
changeip.bat "LAN" static 192.168.0.1 192.168.0.2 192.168.0.4

Look for it under tools/other.

[1] output (labs.bfloch.com)

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