We've already posted some details about our Mango updates to the IMDb application, which were unveiled at MIX11. Our own beloved Integrator, @lbugnion, dives into the steps that were taken to add a new Live Tile on Windows Phone 7 on his personal blog. You owe it to yourself to check out his insights if you are a software developer working with Windows Phone 7.
Here's a taste:
Very important: The pictures used for the live tile must be 173x173 pixels PNG or JPG, and added to the project with the Build Action set to Content. To change this, select the images in the Solution Explorer, press F4 to display the Properties and then change the Build Action to Content, and the “Copy to Output Directory” property to “Copy if Newer”.