Twitter Joins Hands With Ping, Allows iTunes Previews Within the Microblog

Twitter made an announcement that Ping, which is iTunes' social networking service has joined hands with the microblogging service. The most useful feature of this collaboration is the ability to preview songs within Twitter.com itself.

                  Let the awful jokes of the Twitter bird singing begin 
Other benefits include finding out about concerts via venues' twitter accounts, which sync with their own Ping accounts, as well as keep up with events like award shows via live tweets.
Here's a video demo of the integration.