Those are all hand-drawn maps. I don't know the name of the artist but he's pretty famous (for this niche). I'm sure one of the industry pros knows. But what you need is a raster program (Gimp or Photoshop or Paint Shop Pro or whatever), a tablet for drawing, and lots of practice. I've never been able to replicate the style but Torstan, a member here, comes pretty close to this style. We all develop our own style no matter how hard we try to copy something else so my advice is to just plug away at it until you get something nice.