Nope, not at the moment. It's a highly-requested feature, and even the devs want it in pretty badly, but there are some serious hurdles in the way of it being implemented (mostly due to the audio engine). We'll have to see what happens.

Some news about this feature? =]

The problem I see are copyright things. But it would be great if it works :)

i think its mainly copyright issues, already played with the audio engine and i think it'll do fine from a technical standpoint.
There's one way though but its not exactly like "adding an mp3", it works by manually composing music WITH distance and developer sfx assets, very limited and time consuming, but the only way to really add "custom music" to a workshop item at the moment.

Originally posted by snakeeye98:

The problem I see are copyright things. But it would be great if it works :)

And to get back to copyright...... the terrible thing is that its not that much about protecting the artist anymore, but more about protecting and enhancing the profit of a company.
Companies like disney and apple are actively trying to change copyright their way, the more draconian modifications that already happened have forced certain countries to equal copyright violation to physical stealing (law enforcement may hunt down a copyright-infringer like they were catching a bank robber, and courts may impose ridiculous fines on that person).

Upcoming "copyright" modifications described in TIPP/TPP try to make ownership of any piece of media exclusive to a few multinationals.... wich can very well nullify fair use across the whole internet (just look at what already happened to youtube), and throw the media landscape back to some kind of cable television age, where central distribution of information is the only legal way, and where you pay a company ransom to participate, and even more to legally create.