Physician here. I read this paper when it was posted on Reddit a few days ago and it was very impressive.

I'll link to the discussion because the top comment was comprehensive and summarizes the published article:

http://www.reddit.com/r/science/comments/22qhob/laboratorygr...

To address questions of how this can be applied to other organs, growing tissue like a trachea or skin is becoming easier. They grow the cells on a scaffold and then you have a tissue. Organs are much more complex and a penis is an organ. We are not at that level of sophistication to grow an entire, functional organ ex-vivo, at least for human use.