I spent quite a long time trying to figure out how to have a new window open when a link on my blog is clicked on. Hopefully this will save you some time!
Here is the HTML code for the "be kind" button from Shabby Blogs in my right sidebar:
<a href="http://shabbyblogs.com/new" border="0" target="_blank">
Adding target= "blank" inside of the carrot signs causes a new window to be opened when the button is clicked upon.