Either take lessons for a while, assuming you can find a teacher......
 
or, check on line for software that you can load into your computer and as long as you're willing to spend 30 minutes or so a day with it, you can learn on the computer.  We had some of that software around here when the girls were younger. It was like playing a game.... and you learned how to play the piano..... very cool.
 
No, I don't think piano is easy..... to me, guitar was easier.... learn a few chords and you can play lots of songs. With piano, learning how to place fingers as you move up and down scales is important. 
 
I will say this: the piano is the absolute best instrument to know and understand when you are learning music theory. It's all right there in front of you in black and white, in a linear fashion..... unlike most other instruments.

Here's the video I liked.
 
https://www.youtube.com/watch?v=qL3Y9B34_7w
 
and his other tutorials
 
https://www.youtube.com/user/billhiltonbiz/playlists
 
He has a book too, to accompany it

When I went to the IMSTA FESTA in New York last year, there was a company there touting some interactive piano lesson app which actually looked really good. I meant to check it out further when I got home but couldn't for the life of me remember the name so it got forgotten about. I should have realized how easy it was to find it out from the IMSTA website though....so here it is, Playground Sessions, co-created by Quincy Jones:
 
http://www.playgroundsessions.com/
 
 

@spacealf, thanks for the laugh. I think I can safely guarantee that I will not become a one-man band like those youtube videos you provided. I may try and find that Japanese guy's outfit though. That qualifies as business casual, right?
 
@scoot, thanks for the youtube links. I actually found the videos useful. There are a few things there I hope to try this weekend when I get some time to sit and play.
 
@sharke, thanks for your link, as well. That does seem intruiging.
 
@guitarhacker, Piano? Best instrument? You can't even bend the keys. How are you supposed to hit those all important 1/4 tone notes between the semi-tones? I jest, of course. If the layout wasn't so obvious, I don't think I'd be able to do the little on the piano that I can do at the moment.

One lesson he spoke about how chords in the lower octaves could be much more open than the lower, as the overtones helped for form the constistant sound of being that chord.

 
There is a basic rule in theory that notes below a certain octave should never be closer than a fourth or fifth.  The frequencies are so close together that it becomes just mud.  Lower chords are better spaced out, never a third on the bottom.  
 

I swear on a regular piano (not a synthesizer) there use to be more room between and on all keys. Now on a synth like it is only an inch for a key space, where before I swear it was 1-1/4", at least on a guitar somewhat you can pick out the length of the neck you want - 24.75", or 25.5" somewhat, on a piano, no you usually can not do that anymore.

 
Synth key usually are smaller.  They are obviously not meant to be used as a piano performance medium, but more of a musical/compositional aide.   Though I personally hate full sized "Hammer-Action" keys on most electric stage pianos and large synths.  IMO worse than standard weighted keys and nothing at all like a piano feel.  

i would ask around, and find the best teacher in your area.
 
it will short track your learning curve by at least half.
 
it will provide the most solid foundation for learning, which is more important than anything else.
 
 

I guess it depends on which one-person band outfit you choose.
 
https://www.youtube.com/watch?v=9KobTtlkWNM
 
 

Finding a good teacher will definitely speed up the learning process. Putting in the work will also do that. Try to find the best teacher possible.
 
Alternatively, Bastien's Piano for Adults is a great book for learning the piano. There are 2 volumes actually and they really help with not only your piano skills but your music theory skills. You will have to learn how to sight-read but embrace that, being able to sight-read is an invaluable skill and the book does a good job of building up that skill. The reason I recommended the books is because they were designed to take you through a logical progression, so you get from point A to point B as best as possible.
 
Good luck!

Like the OP, I'm in the same boat. I agree that taking formal lessons is the best but if you live in the boondocks like me that's not always easy. I had a look at "Playground Sessions" but it seemed even the advanced lessons were focused on chord/melody style playing. That's great if you just want to entertain yourself at home but that's not how you would accompany yourself on a song you're writing.
 
Lots of stuff on the internet. Learn the chords and the keys then go through Bill Hiltons youtube videos. If you're still dedicated after that I'd suggest checking out "PianoWithWillie". It's not cheap and probably 65% jazz orientated but there's worse things in life than accidently picking up a little jazz theory. The whole point of his site is to learn to play like a real keyboardist would either live or on a recording and how to take chord/melody sheet music and turn it into an actual arrangement.
 
I find the hardest part is just devoting the time. Good luck, mantofini, and have fun!

If you can play the guitar, the it's REALLY easy! So you know chords are build on major and minor triads? And they (for the most part) have a root note, which determines the key? Alrighty then, so if you want to play a D chord? Find the DMaj note (between the two black keys) and build the major chord based on that, just like on a guitar. I would recommend that you learn major chords first, and in a 1/4/5 progression, just like on the Guitar. And add the bass in with the left hand, usually the root note of the chord in an octave. There is no H, so how hard could it be? That and it is much easier to play than the guitar because you don't have to coordinate between the strings, and the pick, fret noise, buzzing, string noise, etc... The guitar is much more difficult to play than the keys. Also and finally, find a song that you want to play, then learn the chords and how to play "that song" Then find another song you want to be able to play? Lather, rinse, repeat. I'm self taught on the keys and not half bad ;-)
 
H-