The nikon is probably the better camera of the two by far!
For cheap software that is very good I know Sparky uses Gimp which is free. It's very much like Photoshop in how it works. It's not intuitive and there is no easy button, but if you really learn it, it's an incredibly powerful program.
For inexpensive editing program take a look at Adobe Photoshop Elements 10 or Corel's PaintShop Pro X4. I'd try to stick to the photoshop only because if and when you upgrade later to a full version of photoshop you are still working with the same interface, your actions, brushes, etc will all transfer. I believe you can pick up elements for under $75 now. You can download the trial and use it for 30 days as well.
It looks like a lot and very complicated when you are at the starting gate and looking at having to learn exposure, composition, post processing, editing, color management.......... It's not that bad and as you start to move forward it will begin to fall in place much easier than it looks.
For the photography end of it you can start with the tutorials here:
Digital Photography Tips and Tutorials
As you are working your way through them and you get questions just ask. There's always someone around to help!