Make sure to learn about "penile rehabilitation." Some doctors are very good about this but I've heard others are not. It basically involves taking daily low-dose Viagra or Cialis to keep bloodflow going. If your doctor doesn't offer this, you should ask (unless, of course, these meds are contraindicated for you for some reason).

There's a good book, though keep in mind that it's a bit dated, called "Saving Your Sex Life: A Guide for Men With Prostate Cancer" by John P. Mulhall, MD. He is the director of sexual medicine at Memorial Sloan Kettering, which is a top cancer center. I had radiation and am currently on androgen deprivation therapy (ADT) so can't answer any specific questions about sex after surgery but it is covered extensively in the book.