...I use Sibelius everyday for everything from simple choral arrangements, hymn settings for choir, and piano music to full orchestra. Professionally, Sibelius and Finale are considered on an equal level... depends which one you started on, actually. This sort of tool is such a necessity for any 21st century professional...though there are countless websites with info, here's how little you really need to get started:
-average computer, running XP, Vista, or Mac OS (If your computer is more than 6 years old, you will most likely need to upgrade. It simply isn't worth the hassle forcing an old box to do this sort of computing, absolutely not worth the few $ you might save.)
- a basic MIDI keyboard controller (these can be had starting at $ 100. )
- You won't need a MIDI interface, as the controllers can connect to a USB port on your box)
- Professional grade notation software. Don't skimp here, as the really inexpensive versions and freebies simply won't do the job... oh, you might be impressed at first, but your needs WILL increase... and then you'll have to RE-LEARN the whole process with different software.
- a set of headphones, which you already have.
That's it. Absolutely unbelievable what you can do now. And the money you spend on the software supports those programmers who are working in a very volatile industry, for a limited # of customers.
A few thoughts on the topic...
We as organists frequently preside over one of the most complex instruments known to man... we learn as much as we can about our chosen instrument, by reading, taking lessons, and listening to others. And, yes, ladies and gentlemen, it takes time. Now, why is it that anyone would expect mastery of a computer-based notation system to be instantaneous? It takes an investment of time as well... the pay-off is incredible.
It is an error of the largest magnitude to assume that you don't need to read music to use one of these programs. There is inevitably some clean-up that needs to be done, or re-formatting...but, with some dedicated practice, you can do this extremely quickly.