One of the problems facing software re-engineering projects is the fact that program source code is invariably stored in ASCII plain text format. This format doesn?t reflect the underlying structure of the program. Consequently, software re-engineering or code migration tools need to unearth this structure. This paper explores the possibility of adopting XML format to represent program structure for software systems, and describes a tool, the XMLizer, which has been implemented to support the transformation of software programs from ASCII plain text format to XML. In addition, the XMLizer allows variable-depth marking up of program structure by using a multi-weight parsing technique. The XMLizer currently supports three languages, Java, PL/IX and Pascal, and can be extended to support others. The performance of the XMLizer in converting PL/IX programs into XML was tested. XMLized output is accessible through an abundance of existing XML tools that can support both analysis and visualization tasks.