How to get an text list of login names for a user group of a windows server

I must copy all login names of a specific user group of a windows server to a 3rd party system. To make it easy I need an text list of the login names. I don't like to copy the login names from the user property dialog and build the list by my own.

I think (and hope) their must be a tool on windows server 2003 R2 to do this task.

Thanks in advance

My solution

After hints of duenni I build this batch file which do the job:

@echo off
dsget group "CN=MyUserGroup,OU=MyOU3,OU=MyOU2,OU=MyOU1,DC=MyDC3,DC=MyDC2,DC=MyDC1" -members >users.txt
echo >usernames.txt
for /F "tokens=*" %%i in (users.txt) do dsquery * %%i  -attr sAMAccountName >>usernames.txt
find /V "sAMAccountName" usernames.txt

In the MMC "Active Directory Users and Computers" right Click on the OU you want to export goto Action - Export list.