How To: Create a shapefile without using ESRI software
Some software developers want to build functionality into their application that can create map data in the Shapefile format. Of course, the easiest way to create shapefiles is to use any one of a number of ESRI products such as ArcView, ArcInfo, and MapObjects.
Use the following source to compile a library suitable for referencing in a VB project. It contains functionality designed specifically for writing the SHP/SHX/DBF portions of the Shapefile format.
It is possible to use the capabilities of VB to read and write files using binary access to create your own shapefiles. You can create the SHP and SHX portions of the shapefile using information found in the Shapefile Technical Description white paper and then the DBF portion of the shapefile using the technical description of that file from Borland/Inprise.