What resources are required for bitcoin mining? What resources do I need to mine for bitcoins?  

Do I need a computer and computer software? 

Do I need a license to mine for bitcoins?
I'm not sure it's worth the bother any more - there's no point at all mining bitcoin with a computer, or even a bunch of graphics cards. It's now done by dedicated mining machines like an Antminer S9 - mining farms have thousands, maybe even tens of thousands of these things in warehouses plugging away at getttibg hashes. You could buy one, join a pool of other people who also have them, and get paid a share of the pools winnings if one member finds a block, based on how much computing power you represent to the pool..

.. but then there's the question of whether your pool will ever find a block, as the only way your machine will return on its investment is if it does, and it's not a sure thing. And maybe the antminer s11 will come along and be 50 TH and the same price as your s9.. and then it makes it a whole lot harder as mining farms get 4x more processing power.. they're much more likely to find a block than you are..

Hmm, so.. look into it some more. The conclusion I came to is that it's just not worth mining bitcoin any more. Maybe some altcoins, but work out how they're best mined and mine them with the best value method

Side pondering: If only satoshi nakamoto had made the work-done something like protein folding, cancer cure calcs, something useful (instead of trying to find a number smaller than another number) all that electricity burnt on this huge distributed computing effort would have had some great benefits