I had to do the same thing, move without either seeing the place or meeting my future flatmate.
Regarding the place: Prior posters covered it pretty well. I don't recall if anyone mentioned http://www.landorslum.com/
. Look at that as another check on the possible landlord of your place. You could also try http://www.backpage.com/classifieds/index
and the local newspaper classifieds to find the place. Finally, I would try posing a housing-wanted ad on craigslist. It's been a very successful tactic in some of my past housing searches and those of my friends.
Regarding a possible flatmate: This is where I ran into problems. Here, the most important thing, assuming you're going to have a flatmate, is honesty. This actually goes for the place, too, but I'll speak of it in terms of the flatmate. Figure out what's vital to you for whatever reason. Do you need a quiet place, or, alternatively, a place where you can have dance parties in the common areas? Do dishes need to be washed immediately after use? Smoking? Pets? Dinner parties? No matter how insignificant or odd the issues, most, if not all, people have things they're particular about, and you need to figure out what those things are. Then make sure you and your potential flatmate agree on those issues.