It's all in photoshop and done with a tablet (intuos). I gave painter a go and it's awesome except i couldn't fix some horrendous colour reproduction (banding) nomatter what i tried, and this seems to be a common problem with it. Doesn't really matter what software you use, so long as you know shortcuts to make your life easier. I'm well accustomed to photoshop so i just use that for everything.
Mainly for photoshop:
Hold down space = pan tool
R = non destructive rotate canvas
F6 = Colour palette
For the occasional perspective guideline or adjustment layer i'll use the mouse, but everything else is done with the tablet. A good thing you may want to do is to make sure you map your tablet in a 1:1 ratio when using Pen (as opposed to Mouse) mode. I have my pen customized so it's easy to toggle between both modes.
I've barely done any painting/drawing in real life, but the same principals apply. If you want to do some quick sketchboard mockups it's easy with a lot of custom brushes (shapes, etc), but it's not rewarding and the end result feels tacky, so i always try and draw everything as if in real life.
This is only a hobby for me i havn't put any serious time into learning any anatomy/proper landscape, so I draw from reference quite often.
If you do have the time and money, the one place i'd recommend checking out is
http://theartdepartment.org/downloads
http://theartdepartment.org/streaming-classes
and
www.conceptart.org for community
And really the best advice is practise do redo repeat do more experiment rinse repeat.
