Add Barcode Reading Support to VB.NET/ASP.NET application

We have developed a VB.NET/ASP.NET inventory/ERP type application. We have had a request to add barcode reading support for day to day products (supermarket, shops etc) into the application.  We have done a bit of research on the net and there doesn't seem to be a well defined way to reading barcodes.  We have discovered the  Smartscan Xpress Barcode - Standard (.NET Component) - V3.x (by Pegasus Imaging Corporation). As i can't find any direct competitor to this applicaiton, i am wondering, does anybody here have any experience in integrating a VB.NET app with a serial port or USB barcode reader? Are there any gotchas we should avoid? Is it better to buy an off the shelf package like the one above, or try and develop our own?  Are there any places or companies who produce code that we should look at?

Thanks