Hello, this is my first time posting on Donation Coder. I noticed that the topic of this thread is very similar to the project I've been working on for the past couple of months. It's called Video in Picture for Vista and has the ability to essentially replicate the function of the program from the OP.
However, I go by it a different way. I use the live previews features of Vista to allow you to crop, resize, and reposition the live previews of windows. You can dynamically resize the live previews by using the scroll wheel of your mouse, the keyboard arrows, or just by dragging the borders. You can also crop the picture to the way you want it by just holding down CTRL and dragging the borders.
The program allows you to create the previews from a scrolling menu or even better, by just minimizing the window you are looking at. If you close the preview and create it a preview from the same window again, it remembers the size and position of your previous menu so you don't have to resize it.
There are some videos and pictures on my website: http://videoinpicture.wikidot.com/
that will show you what I mean. You can also get a copy of the problem off there. It current is in development to get rid of some bugs and streamline it, but it is functional and stable.