The Group Policy Management Console has a script to do it. Assuming you are on 2008 or higher, install the GPMC feature first. Then download the GPMC sample scripts here: http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=14536
From a commandprompt, execute: C:\Program Files (x86)\Microsoft Group Policy\GPMC Sample Scripts> cscript .\ListSOMPolicyTree.wsf
To get a result like this:
=== GPO Links for domain sol.local ===
DC=sol
GPO=Default Domain Policy
GPO=Firewall : allow tools machine
OU=Admin
GPO=Enable Auto Enrollment
OU=Access Groups
OU=Admin Accounts
OU=Role Groups
OU=Service Accounts
OU=Domain Controllers
GPO=Default Domain Controllers Policy
GPO=Enable IPSEC voor DC's in SOL
GPO=WSUS for DC
GPO=ADRAP Settings - old ADST
GPO=RDP Defaults
GPO=ADST new settings
GPO=Enable Auto Enrollment
OU=myOU
OU=Bulk Users
OU=Contacts
OU=Groups
OU=member servers
GPO=WSUS for Member Servers
GPO=RDP Defaults
GPO=Preferences Experiment
OU=Exchange
OU=Other
OU=Test
GPO=WSUS for Test
OU=WSUS
OU=Migrated
OU=Groups
OU=Users
OU=ouA
GPO=GroupA testpolicy
OU=ouB
OU=Smart Card Users
GPO=Enable Auto Enrollment
OU=Users
OU=Workstations
GPO=WSUS for Member Servers
GPO=Workstation Policy (including Vista)
=== GPO Links for sites in forest DC=sol,DC=local ===
CN=Branche1
CN=Branche10
CN=Branche11
CN=Branche2
CN=Branche6
CN=Branche9
CN=Central
CN=Default-First-Site-Name
this mess is my lab 