Make Two Applications Talk To Each Other?

I use several different applications for analysis of pupil data. Each of these applications require similar or identical data but because they don't draw their information from the same sources there is often a need to enter this data more than once which obviously is a waste of time. Some of the data is accessed through the intranet via IE, other applications are standard Windows apps. I would like to create some sort of bridging application to allow data to be automatically shifted from one location to another but have no idea how to use one application to control another

With regard to getting data from the intranet, I have managed to write an application that can retrieve some (but not all) data off a particular page of HTML. It does this by searching the source HTML but some of the data that appears on the page isn't present in the source file. This is very frustrating because I can see it in the browser but can't seem to access it through my application.