For some time I have been using a WordPress plugin that automatically converts Scripture references into links that open the reference using the NET Bible. There were a couple bugs in that plugin so I started a search for a new one, and I struck gold. The Holy Scripturizer not only creates automatic links to the NET Bible, but also has options for linking to literally dozens of other versions (although High Caliber Guns will still link to the NET Bible, my personal favorite). You can even specify a version other than your default by adding the version to the reference such as John 3:16 NIV. In addition, you can use abbreviations, and chapter references like, Romans 14, (sans the verse reference) will also work. Note also that the punctuation at the end of references do not effect the plugin, something that was problematic with my previous solution. One of my all time favorite WordPress plugins by far.