Visit http://www.google.com/adsense and create a new account. If you already have an account you can use that one.
Login to your Google AdSense account and click on the "AdSense Setup" tab then click on the "Manage Ads" link. Here you will see a list of your current ads running with AdSense. The list will be empty if you have just created a new account.
At the top of the list click on the link "Create a new AdSense unit". You will now get a short list of choices of which type of add you want to create. Click on "AdSense for Content". The wizard for creating new ads will now show.
Log into your iCornr account and go to your My iCornrs page and click on your blog. You should now see the forms where you configure your iCornr. Click on the tab named "AdSense". This tab shows two fields called "Google Ad Client" and "Google Ad Slot".
Add the text from your adsense code into the correct field. From the example above you should put pub-3106940239716550 into the "Google Ad Client" field and 5264155810 into the "Google Ad Slot".
Click the save button and eveything is done. Ads from Google AdSense should now be appearing in your posts on the iPhone app.