I’m asking that question of bands and labels that are selling music. Do you sell your stuff in iTunes? If not, now may be the time.

The news today is that Apple’s iTunes Music Store has lept ahead of both Target and Amazon.com to become the third largest retailer of music in America. Only Wal-Mart and Best Buy scored larger market share.

The new numbers considered every 12 tracks sold online to equal 1 CD. And with that formula in hand, Wal-Mart (who also sells online) grabs 15.8 percent of the market, Best Buy scores 13.8 percent, iTunes 9.8, Amazon.com 6.7, and Target 6.6 percent.

We’ve heard time and again that CD sales are slipping, and indeed they are. CD sales during the first quarter of this year were down 16% over last year. Yet during that same time period, digital sales rose 49%. Yeah, I know, digital sales only make up slightly less than 25% of all music sales, but it’s the segment that’s growing. In fact, according to a story on the ABC News site, Nielson SoundScan is reporting that overall music sales for this year are up 14% over last year, and that due to the rise in digital sales.

At a time when a lot of artists are in despair over the decline in CD sales, this strikes me as good news. If you sell music and you aren’t selling downloads, it’s time to adopt the format the market is embracing.

How these numbers would break down for bluegrass music, I don’t know. I suspect they are quite similar to overall industry based on conversations I’ve had with various artists that come through the studio.