Twobbler retrieves latest tracks from a Last.fm user and writes the info of the last played or currently playing track to a text file. This text file can then be used in OBS or XSplit.
If you don't have a last.fm account yet, you can create one here.
The next step is to connect your favorite music service with last.fm (also referred to as scrobbling). A list of sites that scrobble to last.fm can be found here.
Services such as Deezer, Grooveshark, Rdio, Spotify, This Is My Jam, etc.. will let you connect to last.fm directly from their respective account settings.
Services such as Pandora, YouTube, 22tracks, Soundcloud, TurnTable require a browser plugin to scrobble to last.fm.
Chrome users can use this plugin: Last.fm Scrobbler for Chrome.
Desktop music players such as Windows Media Player, iTunes, WinAmp can scrobble through Last.fm's Scrobbler for Windows.
Once you have one or more music services scrobbling to Last.fm, all you have to do is fill in your Last.fm username in Twobbler and click Submit.
The info (Artist + Song Title + Album) of your currently playing or last played track will then be written to a text file located at:
[USER DOCUMENTS]/Twobbler/nowplaying.txt.
Create last.fm account
Scrobble music service to last.fm
Specify last.fm user in Twobbler
Add text source to OBS or XSplit
Download Twobbler
Requirements: Twobbler requires the Adobe Air Runtime (free download).
WingsLTD from Denial eSports was nice enough to do a video on how to set up Twobbler for use with YouTube.