Possible Duplicate: I made a product, now how can I find customers?
I built a prototype for a desktop music app that will keep you updated with music. It has real-time music aggregation, and a local database that holds the data, so you can keep your music links.
How can I promote it to get alpha testers to help me improve it?
If you're at Alpha testing stage, you really need people who are close to you, that can spend time and effort testing and most importantly - providing feedback.
Complete strangers don't generally make good Alpha testers in my experience. Ask friends, colleagues, family etc.
I would recommend you to buy some small amount of Facebook Ads. You can also send the link to your application to all your Facebook friends and ask them to test it. People who know you personally would be glad to help :)