TraxMatch for Winamp - The TraxMatch.com plugin that tells people what you're listening to.

This plugin acts as a interface between Winamp and Traxmatch.com to allow you to display what your are currently playing to other people. Can display through an AIM profile, html profile, or a dynamically generated image. Traxmatch.com account (account is free) is required to use this software.

Another one into the ever crowding sea of now playing plugins but this one works pretty well.
The plugin is fairly unobtrusive and submission updates are pretty much instant once the plugin has submitted them.

Supports html, aim and a generated image to show what you're currently playing and you have control over how they're displayed to an extent.