WARNING: The app is currently in an open beta. Regardless, attempts will be made to push polished updates.
The host requires a Spotify Premium account.
Mixen is an awesome music player for Android with the ability to create a playlist that can be shared with friends near you. No need to be on the same WiFi network, just have the host of the party log into Spotify and bam, you're ready to get the party started. Songs that someone adds to your playlist show up and will be played.
Mixen is powered by Spotify! Therefore, the host of the party needs to have a Spotify premium account.