bizTwist's Corporate Instant Messenger solution is "iChat", and it's free! It is comprised of two components, the iChat client and server.
iChat is a new breed of instant messenger, designed to solve the business needs of companies who want an "inside the firewall" corporate instant messenger. iChat requires authentication and uses your existing infrastructure to accomplish this.
If you have an LDAP v3 compliant directory such as eDirectory 8.5 or higher, you can point iChat to this directory and authentication will take place. You do not need the NetWare Client. Your iChat users will use the same username and password they use to log into the network. One of the best features of this solution is it uses the same user object naming convention you find in your corporate directory. The benefit, you don't have to try and figure out who in the world just sent you a message, because they are using an obscure user name. You now see the first and last name of that individual as it exists in your corporate directory.