I don't think so. What would the cost be for? Yes, Apple would be paying for the storage and bandwith for the downloads which would be significant compared to a song, but not really anything in the big scheme. The reason that we have to pay for songs is that the artists and labels expect to get paid for them. However, the artists and labels pay hundreds of thousands of dollars to create music videos to help sell more albums. So, instead of only having their music video play a few times a day on MTV, they could provide them with single or album downloads for free.
If a music video for a song I really like came with purchase of the album, I would be more likely to buy the whole album instead of just the single. This would create more revenue for everyone with really no additional expenses (remember, they are already creating the music videos no matter what).