Stream music directly from your iPhone or iPod touch with the FireflyMediaServer application, a ported version of the same media service that shares iTunes libraries over your wireless network. Say you're at a friend's place and you want to play a song you've been really into. Rather than handing over your earbuds, you could just log in to her wireless network and stream the song on a proper set of speakers through the iTunes shared library. Setting it up takes a little doing, but it's also very simple. First, you should have already performed the dead simple one-click jailbreak, which will install Installer.app on your iPhone or iPod touch. Now you'll need to run Installer.app and add a new repository to your sources. Here's how that works:
Go to the Sources tab of Installer.app, tap Edit, then tap the Add button and type
http://home.mike.tl/iphone as a new source. After you've added the new source and refreshed your repositories, go find FireflyMediaServer in the Install tab and install it. Once FireflyMediaServer is installed, you'll notice your iPhone or iPod touch shows up in the Shared libraries section in iTunes. The default password for the library is "dottie".
I was surprised at how well this media streaming worked from the iPhone. For example, I was successfully streaming to two different computers at once without a hiccup. Just keep in mind that you'd probably want to turn your auto-lock off while you're streaming to be certain you keep an active wireless connection while you're streaming your tunes and this will likely drain your battery rather quickly. You won't use this all the time, but what a great feature for when you do want it.