I had a problem doing this at first. And I will explain what the problem was so you don’t do the same stupid mistake I did. First you have to login to your Twitter account and then click on Settings.
Then click on the widgets link at the bottom of the menu. You find it on your left side on the page. If you don’t have a widget jet then you have to create one. See the screen shot below.
Click the create new button to go to the settings page.
To make this new widget work on your WordPress blog or any blog you have to add the Url for the website you like to add the widget to. My stupid mistake was that I just added www.Mimmofischetti.com. I pasted the code to my text widget to add it to my sidebar but the only thing I got was a text link. No widget. So I added Mimmofischetti.com whitout the www like you see on the screen shot above. And saved it. And it worked!
So to make it work you have to add the Url with www and without. Pretty simple when you get it. I had to browse the Twitter forums to find this out. apparently a lot of WordPress users had the same problem as me.