One of my favorite sites (and lifesavers) has been Remember the Milk. I've raved about the text messaging reminders, and the fact that you can create custom lists and share them with others, which has made my life so much easier. Especially since I have trouble remembering when to take the trash out. Well . . . sometimes.
So my relief hit an all-time high when Remember the Milk came to the iTunes App Store. And the best part? If you're a proud Pro account holder, it's still free! Free to get organized, free to manage my time, and free to share my tasks with my BF — cause you know, that grocery shopping won't get done on its own.