While on the windows platform it was sufficient to only provide the username and password for the providers APN, with Mac OSX a generic modem phone number is required. This phone number is “991#”. For a username and password for the providers APN you have to consult your provider. The user name for A1 (Austria) is ppp@A1plus.at with the password ppp**.
In the “Advanced” settings choose “Research in Motion” as vendor, “BlackBerry IP Modem (GSM)” as model, “a1.net” as APN!