I was searching for a VBA algorithm for Delaunay when I came across this.  Unfortunately, the VBA code here is poorly formatted and takes some guesswork to straighten out.  I have done so and posted it in the link below.  I'm not sure how to implement the functions so you as the reader will have to figure that out unless the author makes some updates.

My code compiles in Excel VBA, but it is incomplete because of two missing function and the value for EPSILON.  The missing functions are fQuickSortArrayDbl() and fDistance2DPoints().  I created placeholder function stubs just so the code could compile.