Problem
You want to list all the children of an Active Directory container.
Solution
To list the items in a container, use the [adsi] type shortcut to bind to the OU in Active Directory, and then access the PsBase.Children property of that container:
$sales =
[adsi] "LDAP://localhost:389/ou=Sales,dc=Fabrikam,dc=COM"
$sales.PsBase.Children
Discussion
The solution lists all the children of the Sales OU. This is the level of information you typically get from selecting a node in the ADSIEdit MMC snapin. If you want to filter this information to include only users, other organizational units, or more complex queries.