Dim CountyLocations(3) As Location
CountyLocations(0) = New Location(55.852663, -2.3889276)
CountyLocations(1) = New Location(55.956023, -3.1607265)
CountyLocations(2) = New Location(54.840279, -3.2886766)
CountyLocations(3) = New Location(52.819511, -1.8851815)

For index = 0 to  CountyLocations.Length - 1
Dim Pin = New Microsoft.Maps.MapControl.WPF.Pushpin()
Pin.Location =  CountyLocations(index)
UserControl11.BingMap.Children.Add(Pin)
Next

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:wpf="clr-namespace:Microsoft.Maps.MapControl.WPF;assembly=Microsoft.Maps.MapControl.WPF"
    Title="MainWindow" Height="350" Width="525">
    <Grid>
        <wpf:Map x:Name="myMap" ZoomLevel="5" CredentialsProvider="My Key"
                 Mode="Aerial" Center="55.852663, -2.3889276"></wpf:Map>
    </Grid>
</Window>

Imports Microsoft.Maps.MapControl.WPF

Class MainWindow

    Public Sub New()
        InitializeComponent()
        CreatePushPinsWithToolTip()
    End Sub

    Private Sub CreatePushPinsWithToolTip()
        Dim CountyLocations(3) As Location
        CountyLocations(0) = New Location(55.852663, -2.3889276)
        CountyLocations(1) = New Location(55.956023, -3.1607265)
        CountyLocations(2) = New Location(54.840279, -3.2886766)
        CountyLocations(3) = New Location(52.819511, -1.8851815)

        For index = 0 To CountyLocations.Length - 1
            Dim Pin = New Microsoft.Maps.MapControl.WPF.Pushpin()

            Dim CoordinateTip As ToolTip = New ToolTip()
            CoordinateTip.Content = CountyLocations(index).ToString

            Pin.Location = CountyLocations(index)
            Pin.ToolTip = CoordinateTip
            myMap.Children.Add(Pin)
        Next
    End Sub

End Class

Private Sub CreatePushPinsWithToolTip()
    Dim CountyLocations(3) As Location
    CountyLocations(0) = New Location(55.852663, -2.3889276)
    CountyLocations(1) = New Location(55.956023, -3.1607265)
    CountyLocations(2) = New Location(54.840279, -3.2886766)
    CountyLocations(3) = New Location(52.819511, -1.8851815)

    Dim names = New String() {"sam", "tom", "leon", "eddy"}

    For index = 0 To CountyLocations.Length - 1
        Dim Pin = New Microsoft.Maps.MapControl.WPF.Pushpin()

        Dim CoordinateTip = New ToolTip()
        CoordinateTip.Content = names(index)

        Pin.Location = CountyLocations(index)
        Pin.ToolTip = CoordinateTip
        myMap.Children.Add(Pin)
    Next
End Sub