For the Winamp plugin to work you have to start Winamp with the /class flag.
You may also use foobar2000 with foo_winamp_spam. Then set the Winamp "title bar" format string properly in foobar2000's preferences. Example:
Then you can display your currently playing song via Window/Display Current Song (Winamp) or by command:
There are other options as well, see /winamp help for more info.
The source code is available in the repo.