What I want to write is a small app that sits in the taskbar while the user is using other applications. If the user highlights some text in another app (say a browser), can I copy that text with my app sitting in the taskbar and paste it to another file? It would be like doing a Ctrl-C, only with another key code (F9 or something) and this would also dump it to either a file or an object in my app.

It sounds feasible, but I'm not sure how you'd go about copying the text from the other apps.