Walmart, Napster and some other online places sell music, but nothing comes close — market share wise — to Apple’s iTunes.

But the Big Apple might have a serious contender in the already-established Amazon.com, who premiered their online music downloading site this week.

How good is it?

Well, let’s get some comparisons out of the way.

Amazon’s typical song costs 89 cents, compared to iTune’s 99 cents.  An album on Amazon typically costs $8.99, a dollar less than it is on iTunes.

Amazon’s store sells MP3 tracks encoded at a 256 kbps variable bit rate, while most songs on iTunes are encoded as AAC files with a bit rate of 128 kbps (unless you get the more expensive iTunes Plus version).  While AAC is probably a better format than MP3, the bit rate for Amazon is better.  Bottom line: the sound quality is about the same.

Amazon’s MP3s are, well, MP3s.  This means they will play on anything.  Technically, songs downloaded from iTunes will play on anything, too, but you have to convert them.  Without conversion, they are limited to being played on Apple products (iPods and iPhones).

Amazon’s MP3s are DRM-free.  What does that mean?  It means you can copy them, burn them, back them up, whatever, a limitless amount of times.  iTunes just offered DRM-free music through iTunes Plus, but you have to pay something like 30 cents more per song.

iTunes wins out (so far) on selection.  They have something like 6,000,000 songs in its library; Amazon has about 2,000,000, with music provided by just two major labels — EMI and Universal.  But Amazon does seem to have a lot of top hits, and it even has some artists that iTunes doesn’t have. For instance, you can buy each of Radiohead’s albums on Amazon for just $8.99; not one is on iTunes.

I checked out the Broadway musical listings on Amazon, and was, at first, please.  They have a "Broadway" category, whereas iTunes only has a "soundtrack" category (which is mostly populated by movie soundtracks).  Sadly, Amazon’s categorization leaves much to be desired, since they’ve mixed vocalists with Broadway soundtracks.  I mean, "Mary Clooney Sings Jerome Kern" isn’t really a Broadway album.

So my recommendation is this: If you want to download music, start with Amazon.  It’s cheaper and the quality is just as good.  If they don’t have it, THEN go to iTunes.  iTunes is nicely intergrated with the iPod, and it may take an extra step to load your Amazon music into your local iTunes, and then into your iPod.  But it’s not that difficult, and you’ll save some money.

And even if you end up preferring iTunes, you should at least welcome the competition that Amazon offers.  It might force Apple to do better.