mVox USB Speakerphone
Simple and good!
This is a very simple but great speakerphone. You simply plug in to the USB port of a PC and start to use it. There is no button to push.  It works better than many expensive speakerphones cost a few hundred dollars. Most of microphones in PCs do not work because of the annoying echo. But this device eliminates it by a processor inside the box. If you have used Skype before with a headphone, you will appreciate the comfort of using a speakerphone. With out any buttom, the speaker and microphone volume are adjusted by the PC. It takes about 30 seconds to get the right volume and you don't need to asjust it again. This is a great little speakerphone for the VoIP application.