I have developed a very simple program to create Code 128 barcodes in a bitmap, from a string of ASCII. This was a specific requirement a friend had, who wanted to create barcodes directly without the need for fonts, etc. I will make it available here for free download shortly.
I also wrote a barcode scanning program, which does the opposite: takes a bitmap containing a Code 128 barcode, and returns the 'value' of the barcode. Again, this is completely standalone, and requires no extra libraries, etc. I will make this available for download from here.
UPDATE: See the barcode generator at www.alvervalleysoftware.com for further details.