I have been playing with YackPack (www.yackpack.com) and it is great. YackPack is one of the few asynchronous audio conferencing tools that I have seen and this one is Free. Wimba Voice Tools is another such tool but it is not free.
YackPack let’s you set up “packs” where you can invite friends, associates or your students to meet you in the online pack where voice messages and emails can be exchanged in non-real time. So you can access the pack at any time and listen to messages, reply or post your own. You can send voice messages to the whole group or just selected participants. And email is automatically sent out to alert the participants that a message is waiting for them. And it is very easy to use. Did I mention it is Free?
You can even have several yackpacks and tracking activity in various packs is easy. You can also embed the packs into your website or course sites. There are also great tutorials and help support.
I am going to use this for my next online class and perhaps a committee or two. If you are using this in a class, let us know how it is working for you.
P.S. YackPack has just recently added a synchronous chatting component.