<ol>
<li><p>I want to create a scrollable list of pictures fetched from the internet and give the user the ability to click on it. How do i go about doing it in WinForms/C#? Is it possible to add picturebox control/ controls to the listBox?</p></li>
<li><p>I tried adding a list of picturebox into UserControl with AutoScroll set to true, which will give me a feel like using a listBox, Is this a right approach?</p></li>
<li><p>I also tried setting the ImageLocation of the pictureBox to a URI of the image and then called Load() to load the image, it did work, however my Form is freezing up! How do i go on updating each of the picturebox in a sequential way without freezing my form?</p></li>
</ol>

<p>Thank you,
Azlam</p>

I'll answer your third question first, becuase that's the only one I REALLY know the answer to. There's a LoadAsync() method on the picture box that will load the image in a seperate thread and won't hang your app.
As for the other questions, I too would most likely start with a user control and put the images there. The only thing I can suggest would be to first create a user control that has a picture box, and maybe a multiline textbox or richtextbox next to it. Turn off the border on the textbox, and have a slight border around the entire control. This will allow you to display the image, with some text next to it. Then, your actual final control will just be a collection of these controls with the ability to add them as needed.
--my 2 cents...