Note: The ReplaceURLs function posted in the topic linked above has been heavily edited (primarily to remove edit_hrefs) and will only prevent links without a domain (i.e., internal links) from opening in new window. I'm also (slowly) working on adding a check to see if a link does have a domain, is it the same as the domain as the domain set in admin options.
Search is your friend “I was having a mildly paranoid day, mostly due to the fact that the mad priest lady from over the river had taken to nailing weasels to my front door again.”