With many organisations looking at VoIP as a part replacement for fixed and some mobile calls, it would appear natural for Apple to have supported SIP out of the box.
That they didn’t opened up a market for innovative developers to do the job.
One such, Sipgate, has developed a SIP client for jailbroken iPhones, well the first iPhone anyway.
Of course using VoIP over WiFi leads to call substitution reducing the revenues of the mobile operator.
This potential has narked T-Mobile who has been able to persuade a German court to ban the use Sipgate on the iPhone in Germany.
Along side AT&T abhorrence of tethering applications, Apple’s push into the business market is being hindered by their partner carriers.
With companies impacted by the credit crunch, unrestricted handsets such as Nokia’s E71, Sony Ericsson’s Xperia X1 and HTC’s Touch Pro, make better business sense than the iPhone.