for all the Aussies out therr
Here is how you do it
Formatting is stored in:
/System/Library/Frameworks/AddressBookUI.framework/ABPhoneFormats.plist

Copy and paste the following to the US section

<string>04## ### ###</string>
<string>#### ####</string>
<string>(03) #### ####</string>
<string>(02) #### ####</string>
<string>(07) #### ####</string>
<string>+61 # #### ####</string>
<string>+61 4## ### ###</string>
<string>(61) (0#) #### ####</string>
<string>0011 $</string>

All the phone numbers appear nicely
Enjoy...

I've used another one that does a similar thing, however the only problem I have is when I receive an SMS, the pop up doesn't show the contact entry, it just shows the phone number. However when I check in the SMS app, they show up fine.

If a mobile number is entered as 04xxxxxxxx in my contacts, SMS.app picks it up, and the SMS pop up doesn't.

If a number is entered as +614xxxxxxxx, SMS.app doesn't pick it up, and the SMS pop up does.

A simple solution is to enter everyone's number twice; once in each format. But that's not a very nice way of doing it.

Does your plist have the same problem?