Text based format conversion

We need a program that will translate information from one text based format to another. Ideally written in VB.net but this is not essential. The finished program needs to monitor a hot folder for files, when one is detected, it should perform the conversion, and copy the converted file to a specific location. The final product will be running on Windows XP embedded. A full specification of the source and destination formats can be provided. The end of the project will result in a working product and us owning the sourcecode.
Both original and source file formats are both text based and "configuration file" in nature e.g. There are start / end blocks and valuename=value lines.