Apple has begun the process of rolling out 90 second song previews on the iTunes Store. According to a letter from Apple to its music distribution and label partners that leaked online last month, the company is increasing the length of music previews on the iTunes Store in the U.S. from 30 seconds to 90 seconds for all songs longer than 2 minutes and 30 seconds in length. The letter also stated that by continuing to offer their music on the iTunes Store, the labels are indicating acceptance of the new terms, meaning that any label not wishing to participate would need to pull their music from the store. Notably, it seems the lengthier new previews are appearing on top/featured songs and albums first, while many older, less popular titles have yet to see their preview times increased. [via BGR]