Just like facebook has like buttons my service
http://qcl.me nows has a tip me button just for bitcoin. There are two versions, there is a static image, then is a CSS button that can actual display how much you are recommend to tip.
This is a screenshot of the css button, with no amount
This is a screenshot of the css button with an amount
and here is the static image which would mostly be used for forums just like this one
Leave any questions / request / feedback below