Andromeda is a way-groovy PHP app that allows you to stream your MP3 library over the Internet. It takes a little bit of tinkering to get it running, but once it's up, you can put your whole MP3 collection on a low-cost desktop machine, then bring your WiFi-equipped laptop into another room and listen to it. What's more, you could leave your MP3 collection at home and use your DSL link to stream your MP3 collection to your machine at work; if you're staying at a hotel with broadband in the room, you can listen to your collection on the road.
There's gonna be a whole lot of these things, and each one is going to expand your ability to enjoy your lawfully acquired media. I love the idea of turning a cheap-ass Linux box into a home entertainment server, filled with ripped DVDs, scanned e-books, captured digital television programming and MP3s, so that no matter where I am -- home or away -- all my media will be no farther than the closest open wireless network.
Of course, there's a good chance that making tools like this will be illegal in a year or two. Thanks, Hollywood.