Hi, 

We don't offer a Tooltip property for the ColumnHeader, however you could specify one if you use the HeaderTemplate property. 

However, the only way you'd be able to bind to your DataSource is via a Binding, where you pass in the source. 

So, for example, if you had a view model defined as a StaticResource. 

{Binding Source={StaticResource yourViewModelKey}, Path=Column1.Text}

-SteveZ 

http://msdn.microsoft.com/en-us/library/system.windows.controls.tooltipservice(VS.95).aspx

However, it'd basically look like this:
 <ig:ImageColumn Key="ImageUrl">

                    <ig:ImageColumn.HeaderTemplate>

                        <DataTemplate>

                            <TextBlock Text="My Image Column">

                                <ToolTipService.ToolTip>

                                    <ToolTip Content="This is my tooltip for my Image Column"/>

                                </ToolTipService.ToolTip>

                            </TextBlock>

                        </DataTemplate>

                    </ig:ImageColumn.HeaderTemplate>

                </ig:ImageColumn>

-SteveZ