If you're on a budget, I've heard good things about GIMP It's very similar to Photoshop - plus its free!. Also OpenCanvas is something that a few of the japanese fanartists seem to favour, I think its designed to work with tablets, with PS you need to fiddle with the settings to get a nice fluid line when working with a tablet, but OC seems already set up for that.
OC doesn't have all the features of PS though, its really a drawing/painting program so it doesn't have as many effects etc as PS. So it depends on the kind of art you want to do. OC is about 30$ iirc. Whereas PS is....about $400-600 ouch!
unless you borrow it from the internet *cough* Photoshop elements is cheaper though, but to be honest I have no idea about it as I've never used it.
You can probably download a demo of each and play around to see which suits you best.
As for resources etc. I just google as and when, I've found many good tutorials that way - usually because I'm searching for something specific. DA has some good tuts and they're usually written in an easy to follow way.
Also, as you're going to be using a tablet you'll want to improve on your pen skills in general. So don't limit yourself to online tuts, it will be worth getting a book on figure drawing (I'm assuming you want to draw figurative stuff)
http://processjunkie.blogspot.co.uk/2007/09/best-figure-drawing-books-ever.html
^OK so this is technically online stuff, but basically a few good figure drawing books can be downloaded for free there.
Personally I'd avoid anything talking about 'how to draw manga' etc, because thats just teaching you a particular style (and often not even a very good manga style) It's just one rung up from copying/tracing.
Whereas general figure drawing books will give you a good foundation on which to build your own style. I've found that when I've gone back to look at my favourite artists after reading these books I'm able to break down their art, makes it easier to see how they've done it.
Phew, I'm rambling again.