There is an interesting discussion right now on artima developer discussing the ‘Big Rewrite’ – if you’ve worked in IT for long enough then surely you too have worked on at least one project to replace one system developed with technology X with latest technology Y.
This is an interesting read since there are many more problems with this type of project compared with a ‘green field’ development project, mainly political, strategic, and ‘historical-bagage’ related, all which add up (usually) to a difficult project.