Application/Script for Phone Message to Webpage Like Audio Blog

I am looking for some one with experience on creating VOIP related applications and/or Audio Blogs. Need to have a solution that will allow people to call a phone number and leave a message on their assigned box number/code. Then the user should be able to go to his/her webpage, login and see the messages by date that he or she recorded via the phone. This is sort of like a voice mail messages retrieval via the web, but I need one phone number only and then the user will enter a code to allocate the message to his/her user ID mailbox/space. This is pretty much like an Audio Blog where people can leave an message via phone and it will show up on the web blog as audio that can be played. I am not a technical person so I'm not sure what it is involved, but since Audi Blog are all over this days, I can imagine that there are already similar solutions. I need some one to tell me what this things would entail from getting phone service for the number and mailboxes and the player like Flash audio etc that would be needed. Also Im not sure what the audio format of the message would be if mp3 or Wave, etc. Thanks, Duriti.