I personally use Weather Eye via Blackberry App World. It will depend on your theme preference how it will look but after you d/l the weather app of your choice go to that icon, once you have highlighted it hit the BB button and you can choose to move it to one of your primary apps(first couple of apps, usually first 5-6 show up on main screen depending on theme). I found a 3G inspired theme that shows my weather at the top and center of my main screen. Good Luck! Play with your phone and keep asking questions. You'll get it figured out.
ha. i guess i type like a man!