A lot of mobile phone speaker manufacturers seems to have dumped sophisticating devices and instead have started putting out more minimalistic styled simple devices.
The Altec Lansing M102 Octiv Mini is one such button-less device that is operated by an app-enhanced iPhone 4 or iPod Touch. Take away the iPhone app and the Octiv Mini is a basic iPod speaker. It's not a complete plug-and-play device though, for you have to manually launch the app to make use of some features. But playing music is a straight forward affair.
The volume range is good, and it has a fairly good sound for such a small speaker. Be aware that you have to change the volume on your iPod/mp3 player itself, as the speaker has no controls on it.
The product also ships with a kind of multi-plug - a single adaptor with an interchangeable pin that allows you to use any of the standard pins available without adding any bulk. Perfect for frequent travelers.
Read More here: Review: Altec Lansing M102 Octiv Mini