Here is a script I wrote to move PCs from one domain to another. Just leave off the join command if you don't want to add back toa domain.
This script uses a text file to get the workstation names, so you can do a batch of computers easily. You will need to edit with your domain admin ID & password info.
'==========================================================================
'
' NAME: NetDomJoinWorkstations
'
' AUTHOR: Mark D. MacLachlan , The Spider's Parlor
' URL:
' DATE : 6/24/2003
'
' COMMENT: Joins computers to a new domain. Edit domain name,
' user ID and passwords below. Uses a workstation list wslist.txt.
' Modification 7/28/2003 to include Remove command. Suggest synchronizing old and new server passwords
'
'==========================================================================
On Error Resume Next
'open the file system object
Set oFSO = CreateObject("Scripting.FileSystemObject"

set WSHShell = wscript.createObject("wscript.shell"

'open the data file
Set oTextStream = oFSO.OpenTextFile("wslist.txt"

'make an array from the data file
RemotePC = Split(oTextStream.ReadAll, vbNewLine)
'close the data file
oTextStream.Close
For Each strWorkstation In RemotePC
'Do something useful with strWorkstation
Call WSHShell.Run("cmd.exe /c NETDOM REMOVE " & strWorkstation &"/Domain:<domain> /UserD:<user> /PasswordD:<password> UserO:<user> /PasswordO:<password> /REBoot:30000"

Wscript.sleep 15000
Call WSHShell.Run("cmd.exe /c NETDOM JOIN " & strWorkstation &"/Domain:<domain> /UserD:<user> /PasswordD:<password> UserO:<user> /PasswordO:<password> /REBoot:0"
Next