For many reason, you might want to have pretty twitter button for your blog that do not have plugin allowed such as Blogger, Tumblr, etc.
First of all, access to http://www.twitterbuttons.com/, and you shall be able to view like the above image.
Enter your twitter username and select your logo.
Next, select the Select button and a code will be appear. For MickGenie.com, I am applying it to the sidebar.
Get your twitter button by today too 🙂