TG,
Late extract addition seems to be practiced by many. It involves adding about half of the extract with 10 minutes left in the boil, or at flameout letting the wort sit for 10 minutes before cooling. There are a few advantages that I am aware of. Extract caramelizes during the boil, so a late addition will reduce that impact. The result is better fermentability, lighter color and flavor (which can be difficult to acheive with extract). Also, because you are boiling a lower gravity wort, you get better hop utilization. That helps to get more hoppy goodness out of every ounce.
Stunna,
The 3 week secondary is for clearing and bulk aging. There are MANY differing views on this procedure (and thread counts to match). I have used a primary only for this beer both times, but try both and see what works best for you. And let us know how it turns out.