Problem
You want to list all the members in a group.
Solution
To list the members of a group, use the [adsi] type shortcut to bind to the group in Active Directory, and then access the Member property:
$group =
[adsi] "LDAP://localhost:389/cn=Management,ou=West,ou=Sales,dc=Fabrikam,dc=COM"
$group.Member
Discussion
The solution lists all members of the Management group in the Sales West OU. Since Active Directory stores this information as a property of the group, this is simply a specific case of retrieving information about the group.