Just put it in my website footer [0]. Flattr is very flexible. You can use various methods with more or less or no JavaScript. Also you can link stuff like Github, so starring a repo leads to flattr compensation.
Yeah, I just added it to http://www.gwern.net/ . At first I was all 'o.0 you expect me to load a bunch of JavaScript just to add a button' but then I spotted that there was a purely static version and added it without a problem. We'll see how it goes.
[0] http://beza1e1.tuxen.de/articles.html