We have been asked to produce a logical application and infrastructure diagram for an existing system which is in the process of been transferred to a different server. After some searching on Google we have not found any guidance on what this sort of diagram should containing, does anyone have any links or suggestions?
Probably what you need is to create UML diagrams, you can use CASE Applications like MS VISIO, Enterprise Architect (EA), StarUML for generating such diagrams.
For reading more about UML see: http://www.tutorialspoint.com/uml/uml_deployment_diagram.htm