If you create a new point layer with this projection you can use your lat/long values.
_myPoints = New FeatureSet(FeatureType.Point)
_myPoints.Projection = KnownCoordinateSystems.Geographic.World.WGS1984
Dim c As New Coordinate(53,-120)
Dim p As New DotSpatial.Topology.Point(c)
Dim currentFeature As IFeature = _myPoints.AddFeature(p)