From Annie's Props:
L$200
The AP Answering Machine is designed to allow anyone to leave text-based messages for specific people without using offline IMs. If you would like to allow friends, customers, group members, etc., to leave messages that you (or another designated user) can pick up when in-world, this is the perfect solution. It's also a great way for small groups to stay in contact without using the more invasive offline IM.
The AP Answering Machine is easy to set up and use. It supports mailboxes for up to 12 users. It is modifiable so that you can change the appearance to suit your home, business, or group.
Messages may be left in open chat or on a private channel.
In-world: http://slurl.com/secondlife/Sylvina/205.568/205.833
SLExchange: http://slexchange.com/modules.php?name=Marketplace&file=item&ItemID=198533