Windows: The Hype Machine has long been one of the best music discovery services out there, featuring the most talked about tracks from popular music blogs around the net. Hypegram is a compact desktop player that grabs tracks from the Hype Machine.
Those of you that use the Hype Machine have probably noticed that the site now nags you to register after listening to a few tracks, which is annoying. If you'd rather not register, Hypegram is the perfect way to get around those nags. Just fire it up and start listening to the popular feed, the latest music featured on the Hype Machine, or even search for a specific genre or tag. If you do have a Hype Machine account, you can also listen to your loved tracks and subscribed blogs, plus you can love tracks right from the interface. It's great for discovering new music without having to cultivate a radio station or do any other kind of work—just listen through the infinite stream and click the heart button if you like a track.
Hypegram is a free download for Windows only.

iOS: Ever wanted to start your own radio station, but didn't want to go through all the trouble of actually licensing music or really working for it? Wahwah.fm is a an iPhone app that pulls your pre-existing music library from your phone and allows you to broadcast it to the world.
Music sharing service This Is My Jam has been in private beta for a while, but today the service opened its doors to all users. The idea is simple—when you sign up, you pick a song that you're in love with or that's just been in your head, and set it as your jam. Share it with friends, meet other people based on their jams, play them, leave a comment, follow them, and discover new tunes in a simple, fun to use webapp.
Reader Casey wanted to make a Spotify playlist based on Billboard's Top 100 Singles of 1993, but didn't want to go through the legwork of finding and adding 100 different songs to a playlist. After a bit of searching Casey's solution was to work a little spreadsheet magic.