essentially you can do it in a couple of ways.
The simplest is to do this in HTML
<a href="thepage.htm" target="_new"> click here to open window</a>
Alternately you can get much more control by using javascript. There is a method in javascript coincidentally called window.open that handles this for you. It allows you to set size, position, what toolbars to show, whether the new window has scrollbars etc. It might look something like this in its simplest form.
<a href="javascript:window.open('thepage.htm', '_new', 'width=400, height=300'😉;" > click here to open window</a>
this opens a window that is 400 pixels wide and 300 pixels high. No scrollbars, toolbars, statusbars, not resizeable, nothing. If you don't tell it something in the list of features then it won't turn it on.
Here's a reference on it.
http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml/reference/methods/open_0.asp
sloppy of me.
<a href="javascript:window.open('thepage.htm', '_new', 'width=400, height=300'😉;" > click here to open window</a>
will work but the original page will navigate as well, which is wonky.
you need to do this.
<a href="#" onclick = "javascript:window.open('thepage.htm', '_new', 'width=400, height=300'😉;" > click here to open window</a>
or you could do this
<span onclick= "javascript:window.open('thepage.htm', '_new', 'width=400, height=300'😉;" > click here to open window</span>
but then you would probably want to change the cursor style for the span tag to "hand".