This tutorial is only applicable to Windows users, as the issue I'm trying to describe here is solved out of the box for Linux users with applications like Amarok, Rhythmbox or Qmmp.
Years ago, when Last.fm was taking the first steps, developers have released a lighweight Winamp plugin (DLL file) that let's you scrobble your music. The plugin was only 224 kilobytes, placed in Winamp's
Time was passing by and the plugin was replaced with the dedicated application called Last.fm Scrobbler. This app was consuming wast amount of PC resources, stealing almost 40 megabytes of RAM. As soon as the Scrobbler was released, the plugin was gone. For me it was too much.
Hence I am sharing the plugin on my website so that you can always pull it whenever you have a need in case this mirror is dead.