From what I gather, you have to pay to use this site and the easiest way to log into it is though a website called bigpond.com. The charge for using the site appears to be around a dollar per day.
You will have to use your card details to pay to use this site.
To log in, you will need to provide a phone number and an email address. You will also need to create yourself a password to use it.
It appears that you can also get Airg divas for your mobile phone. I have not been able to find out much information about what this website is and what it is used for. It seems as though it may have changed its name because there is no direct link to it thought the web.
Airg divas was not designed primarily for computers and so it is proving difficult for me to tell you what to do for the best. The only thing I can suggest you do is see if any of your friends use this programme as they will have more information on how to access it.