Apple iTunes' biggest competitor – eMusic – has announced that its catalogue now includes more than 3.5 million tracks. The company recently added 43 new record labels and aggregators, including German electronic label Kompakt, indie rock label Constellation Records, and indie pop/rock/electronic label Iamsound Records.

eMusic sells its music by subscription - users pay a monthly fee to download a set number of tracks per month - but doesn't encrypt the music. Everything is sold in high bit-rate MP3 - audio files that can be played back in iTunes, on iPods or using any other music player.

eMusic also using this week's South by Southwest (SXSW) event in Texas to record a showcase event of up-and-coming artists. A free sampler featuring eMusic showcase artists plus more info about SXSW is available for download from eMusic.