Voici une petite requête WMI simple mais efficace pour obtenir la liste des partages d'une machine :

PS > Get-WmiObject Win32_Share

Name         Path                                                      Description
----         ----                                                      -----------
ADMIN$       C:\Windows                                                Remote Admin
C$           C:\                                                       Default share
homes        C:\homes
IPC$                                                                   Remote IPC
NETLOGON     C:\Windows\SYSVOL\sysvol\powershell-scripting.com\SCRIPTS Logon server share
Profiles_UPM C:\Profiles_UPM
SYSVOL       C:\Windows\SYSVOL\sysvol                                  Logon server share

Pour obtenir les partages d'une machine distante, il suffit d'ajouter le paramètre -ComputerName MachineDistante :

PS > Get-WmiObject Win32_Share -Computer Serveur01