I won't go through the basics of Org-mode here -- this has been documented very well already. I can recommend reading the reference manual; the web is full of useful tips, and the org-mode mailing list is very nice - and org-mode author Carsten Dominik is amazingly responsive.
Traditionally, I've found it hard to keep track of the things I need to do, paying bills and sending in forms on time, and so on. I solved that using some techniques like GTD ('Getting Things Done', or 'To-do lists on steroids') -- I am using it in a dilluted form that works well for me. Spending so much time with computers, it's only natural that I want some computerized to help me with that (and keep a Moleskine notebook as a low-tech satellite system). There is some dedicated software and some webapps to do this, but they never really appealed to me - they are quite rigid, and I am very picky when it comes to quick navigation, not requiring mouse operation, and so on. Of course, you wouldn't expect different from an emacs user.
So, how does org-mode solve this? In org-mode I just keep all my notes (to-do items, appointments, meeting notes etc.) in plain-text files. Within these text files, I can organize items hierarchically, ie.
* item i * item ii ** item ii.a *** item ii.a.1and so on. Org-mode gives them some funny colors, allows you to show/hide part of the hierarchy, and so on. This is excellent for notes, and that makes org-mode already quite useful, even if you don't use anything else.
Still, you might. So, you can add dates to items, say:
* TODO: fix my bike SCHEDULED: <2009-03-18 Wed> :home:Org-mode will recognize this as a TODO item, and recognize that you'd like to do it on a certain day. The :home: is a tag, which means that this is something to do when I'm at home; alternatives could be car or work, but tags can be anything; we'll see how tags come in handy.
The 'magic' now is that you can generate an agenda (week, month, year, filtered) or todo-list, which takes the items from all your org-files, and shows what to do today, this week, ..., and you can filter by tag. Thus, you can have a specific TODO-list for the office. It works really nicely.
Org-mode also allows you to export your todo-lists and agenda's to webpages. You can mark your TODO items as 'DONE', and move them to an archive file. You can have recurrent items. You could add, say, 'MAYBE:' and 'CANCELLED' to complement TODO/DONE. Just about anything is configurable.
And of course, it's all plain-text. This makes it easy to script, and it will work well with a revision control system, such as subversion or git -- and through that, you can easily use org-mode from different computers, home, office, anywhere.
So, with this entry I hope to encourage everybody who likes to manage their time with emacs to try org-mode -- and I only scratched the surface. You can start using it as an alternative to simple text files for writing notes, and then slowly define your very own 'best way' to handle all the other things.
Let's end with some interesting links: