ChartTitle Object [Excel 2007 Developer Reference]

Remarks

Use the ChartTitle property to return the ChartTitle object.

The ChartTitle object doesn’t exist and cannot be used unless the HasTitle property for the chart is True.

Example
The following example adds a title to embedded chart one on the worksheet named "Sheet1."

With Worksheets("sheet1").ChartObjects(1).Chart
    .HasTitle = True
    .ChartTitle.Text = "February Sales"
End With