Some peeps get weather automatically on their calendars like with google calendars... but does that translate over to your phones? You can add as many locations as you want.

Its super helpful for me, especially when planning a trip or traveling. I read a fantastic article on this over on the Apple Blog, and since he did such a great job, I will just link to it rather than try and re-create that post.
You can download a Free 30 day Trial by clicking here ( which is what I did to make sure it's as cool as it seems) but even so it's only $10...