Step 1: Set up your a network using Airport call it whatever you like, I called mine iPhone Tether. You can protect yours if you wish I was in a rush so I didn’t.


Step 2: Open up System Prefs, go to Network select Airport (on the left side). I set up a location also called iPhone Tether you don’t have to. Don’t worry if you don’t have the same settings as me just make sure you have created the network from your mac. Select Advanced.

Step 3: Under TCP/IP select using DHCP with manual address then enter any IP for your Mac. I used the one suggested by NetShare.

Step 4: Select Proxies and tick SOCKS Proxy. In the SOCKS proxy server enter a similar IP address as your Mac’s one this will be your iPhone’s IP.

Step 5: Click OK and then click Apply in System Prefs.
Step 6: Under Settings on your iPhone select Wi-Fi and connect to the network you just created. Tap the little blue arrow next to the Network name.

Step 7: Go to Static. Enter the same IP address for your iPhone that you put in the SOCKS Proxy.

Step 8: Open NetShare, open your browser on your Mac and enjoy!
P.S When your iPhone goes to sleep or you exit the NetShare application it will quit and your Mac will have no internet access via your iPhone.
[Via Macrumors]