AirPort Express is a Wi-Fi base station from Apple. But you can us it for much cooler stuff …
You can use it only as a wifi base station if that what you want. But the cool thing is that it has AirPlay music streaming built right in. So you can easy set up and stream music directly to your home speakers.
Just connect your speakers to the AirPort Express unit and enable the AirPlay funksion in the unit.
… and you can have multiple units Ariport Express streaming music in any room in the house. example, one in the kitchen, in the living room and one in the bedroom, etc.