The new series of Nokia Lumia smartphones running on latest Windows Phone OS 8 can be used as a modem to connect to internet from PC or any other device which has WiFi connectivity. Nokia Lumia smartphones comes with powerful processors and lovely user interface of Windows Mobile OS. The biggest advantages of Lumia smartphones compared to other Windows Mobile OS running phones is Nokia's proprietary exclusive apps such as here maps, Nokia Drive+, Nokia Music etc.
Though in this post, I am showing you how to use Nokia Lumia smartphones as modem to connect to internet from PC, it works fine for all the other Windows Phone OS 8 running smartphones such as HTC 8S, HTC 8X etc.

Using Nokia Lumia Smartphones as a modem to connect to Internet from PC or WiFi enabled devices

Step 1: You need to subscribe for the Data connectivity from your cellular network provider.Nowadays there are very attractive and affordable tariff plans based daily , weekly or monthly plans are available. Even you go for pay as you use also but it will charge you more money.
Step 2: Enable Data service by going to Settings->Mobile Network->Under Data connection select on from the drop down list. This will enable the internet on your phone.
Step 3: Confirm that your Nokia Lumia phone is connected to the internet
Step 4: Go to Settings once again and tap on to 'Internet Sharing'.
Step 5: Slide the bar to right to enable. Once the internet Sharing is enabled, you will see option to setup.
Nokia Lumia WiFi Hotspot
Enable internet sharing and Tap on to Setup
Step 6: Tap on to Setup.  Enter Broadcast name. This is nothing but your WiFi hotspot name. Choose your desired password and save the changes.
Nokia Lumia Tips
Enter Broadcast name and desired password

Step 7: You are done, Now your Nokia Lumia WiFi Hotspot name will be visible on all the WiFi enabled devices. Just enter the password to get connected to your Nokia Lumia device internet. You will in your phone how many devices are connected to your WiFi Hotspot.
Do share in the comment section if you face any difficulty in following these steps.

Nokia Lumia phone which can be used as Modem

Nokia Lumia 1020 as modem/wifi Hotspot
Nokia Lumia 920 as modem/wifi Hotspot
Nokia Lumia 925 as modem/wifi Hotspot
Nokia Lumia 820 as modem/wifi Hotspot
Nokia Lumia 625 as modem/wifi Hotspot
Nokia Lumia 720 as modem/wifi Hotspot
Nokia Lumia 620 as modem/wifi Hotspot
Nokia Lumia 520 as modem/wifi Hotspot