GeoMerge is a utility that lets you merge two or more shapefiles or  TAB files into a single shapefile.

Select two or more shapefiles or TAB files that are to be merged, and click the ‘Merge Files’ button. The files will be validated for a common schema. If all of the files selected have exactly the same column definitions in the .dbf file the records and shapes from each individual file will be concatenated into a new shapefile.

GeoMerge currently only supports :

• ESRI Shapefile
• MapInfo TAB

GeoMerge is FREE for Download! Just download and run the GeoMerge.exe file to start the installation procedure, then follow the instructions displayed on your screen.

Via http://www.vdstech.com/geomerge.htm