Personal Hot Spot doesn't appear in my settings ?

Go to your settings, then general then onto network and it should be in there.

I have the same problem. Just upgraded (in the "about" menu it says Version: 4.3 (8F190)) and there's no "Personal Hotspot" menu!! I using Danish language.

The first 5 menu items in Settings are:

1. Airplane Mode
2. Wi-Fi
3. Notifications
4. Location Services
5. Carrier

And in General Settings > Network:
1. 3G
2. Mobile Data
3. Mobile Data network
4. Data-roaming
5. VPN
6. Wi-Fi

What the h... am I doing wrong???

check this:

http://support.apple.com/kb/HT1937?viewlocale=en_US

check your operator there

But why apple tied it with the telecom companies ?

Apple just makes the hardware/software. Apple doesn't own any networks. It's up to the carriers/providers to decide who uses their network and how. Some offer tethering/Hotspot, some don't. It's that simple. Complain to your carrier. The feature is built into the OS, but will only appear if your carrier supports it.

Apple doesn't own the network? They certainly own the hotspot on the iPhone!

In order to get a better deal with the carriers (contractually and financially), Apple offers tethering as an added incentive. Technically the wifi hotspot and the cell data network are two different networks and it is just a matter for the device (iPhone) to route between them. Neither network has a technical dependency on the other. Just like any other router in existence, iPhone would do this by default. It is Apple's choice to then further add this limitation to the device as a 'feature'. This is a case of revenue ahead of the (end) customer. The best way to benefit is to be an Apple shareholder 🙂

This would make more sense (or any sense) if Apple actually operated a 3G network, but they don't. In order for the Hotspot or tethering to work a user first has to connect with someone who provides 3G services (Apple doesn't do this) and then the transmitter is turned on to transmit what is receive via 3G via WiFi. So the hotspot is worthless unless someone is providing the 3G data stream. If the service provider for your iPhone does do provide a data stream for a hotspot there is no way the iPhone can acquire the data stream and broadcast it.

So the revenue stream end only has to do with the provider, Apple gets the same amount of money either way via the sale of the iPhone.