Streaming music from your PC to your phone is a nice alternative to music locker services like MP3Tunes and mSpot, which require you to upload your music to a server on the Internet before you can access it on your phone. Simplify Media had a great iPhone app that performed this function, but Google bought the company earlier this year--presumably to integrate it into some sort of future music service for Android--and discontinued the iPhone app. I've been looking for a viable replacement ever since.
Today, I found it: ZumoCast. It's brought to you by the folks who run ZumoDrive, a cloud-based storage service. But where ZumoDrive charges you a monthly fee for cloud-based storage beyond 2GB, ZumoCast is entirely free.
To get started, download the free client software for PC or Mac and register with the service. The client scours your file system for music and video files. Then, download and install the free ZumoCast app for iPhone (and iPod Touch and iPad), which launched today.
When you launch the ZumoCast app on your mobile device for the first time, be sure you use the same e-mail address that you signed up with--failing to do so might require you to uninstall and reinstall the app. (There's no easy way to log out or change the e-mail address associated with your account.) The iPhone app takes a few minutes to connect to your library for the first time, but once you're done, you have on-demand access to every song that the client found on your hard drive.
The experience isn't perfect--ZumoCast found only about 3,800 of the more than 4,000 songs on my PC, and the sound quality was a little warbly when I listened over AT&T's 3G network rather than a Wi-Fi connection (which sounded excellent). Unlike a music locker, ZumoCast requires you to leave your home PC on and iTunes open in order to work, although the ZumoCast PC software has a helpful (if energy-sucking) option to turn off your computer's "sleep" mode so your music playback isn't rudely interrupted while out of the house.
Also, I wish there were more ways to listen to songs--there's no queuing, for instance, so if you select a new song it interrupts your currently playing selection. But you can shuffle songs by album or artist, as well as all songs in your library. And I was very impressed by the integration of album art throughout the app, something that a lot of other services can't seem to get right.