There are a plethora of different applications available for using wireless loudspeakers. I will highlight some of these applications and also offer some advice for avoiding mistakes when installing speakers.
One common application for using wireless speakers as shown at http://www.amphony.com/products/wireless-speaker.htm are outdoor events. It is often a hassle to run wires from inside the home to the outdoors. A wireless connection is the logical choice. Obviously, depending on what type of audio source you have, you might either prefer traditional wireless speakers which are bundled with the transmitter or Bluetooth wireless speakers. If the audio or music which you are streaming is located inside of your house, you will need speakers which come with the transmitter unit. The transmitter can connect to your source. It will send a wireless signal from inside your home to the speakers.
Usually, these types of wireless speakers have a fairly long range. In contrast, Bluetooth wireless speakers are optimized for streaming from a cell phone. The range of these types of speakers is typically less than 50 feet. In some cases, the range can be as low as 20 feet. Obviously, for using Bluetooth speakers your phone would have to be in fairly close proximity. I would not necessarily recommend using Bluetooth speakers for outdoor events because if the line of sight between your phone and the speakers are blocked by people then the connection might drop. That would cause an outage in the music.
Another reason for using traditional wireless speakers over Bluetooth speakers for outdoor gatherings is that most Bluetooth speakers are single speakers which means that the left and right speaker are usually in one box. That limits the stereo separation of the signal. In an outdoor environment, it is fairly important that individual speakers be spaced fairly far apart from one another. You will not have good coverage of the sound if you bunch up all of you speakers in one spot. Therefore, Bluetooth speakers are usually not very useful for outdoor applications.
There are wireless speakers available which allow transmission of the signal to more than two speakers. I recommend to space all of the speakers evenly apart such that every speakers facing towards the area which is frequented by your guests. Obviously, when placing the speakers it is important to make sure that each speaker is within reach of a power outlet. You don’t want to run wireless speakers from batteries because batteries will be depleted after a few hours. Instead, connect each speaker to its outlet by using a wallwart power supply.