UPDATED HERE!!
Mike Walsh has posted his comments on my webparts. Mike's right; I only provided installation instructions that could be understood by developers (since the Dev&IT-Pro Days everybody knows that developers are from another planet!). So thanks to Patrick's excellent post on deploying webparts, I had no excuses left to not provide an easy installation. :-)
Now I only have to create nice site for my webparts ... If I only could find some time ...