A couple of tips and tricks for Telstra iPhone users…
If you want to check out your usage, SMS the word “USE” to 176 and you will receive a text message with your data usage.
Get Telstra Usage data by SMS
Reply with the letter “m” for a detailed breakdown.
Also Telstra have just sent through a carrier update in iTunes for iPhone users to enable free tethering!
It just uses the data component of your monthly plan.
Internet Tethering with Telstra