I got this from somewhere once, seems to work

Dim PortalAlias As New PortalAliasInfo

Dim portalAliasByPortalID As PortalAliasCollection = New PortalAliasController().GetPortalAliasByPortalID(SOMEPORTALID)
            If (Not portalAliasByPortalID Is Nothing) Then
                Dim enumerator As IEnumerator
                Try
                    enumerator = portalAliasByPortalID.Keys.GetEnumerator
                    Do While enumerator.MoveNext
                        Dim SomeString As String = StringType.FromObject(enumerator.Current)
                        PortalAlias = portalAliasByPortalID.Item(SomeString)
                    Loop
                Finally
                    If TypeOf enumerator Is IDisposable Then
                        DirectCast(enumerator, IDisposable).Dispose()
                    End If
                End Try
            End If