My esteemed corp mate Mr Skoll has documented his recent victory for internet spaceship science over the ignorance surrounding things that go pew pew and how they may or may not hit other things.
Not like I had any doubt that the implementation of chance to hit wouldn't match up with the design, but Azual's post prompted me to make a spreadsheet I've been meaning to make for some time.
The spreadsheet can calculate chance to hit given the parameters you feed it and puts this info into a handy graph.
You can have a look at it here.
If you think it might be useful to you, you can make yourself a copy (File > Make a copy) and play with the numbers in the white cells.