For the adventurous among you, the Barcelona transport site is http://www.tmb.net/en_US/home.jsp. Quickest public transport from the airport to the hotel seems to take at least 40 mins. I found the site recognised "Barcelo Sants Hotel" but had trouble with everything I tried for "airport", but you can click it on a map.
Taxis are said to take 15 mins, and according to my 8 years old guidebook "un rebut si us plau" or "un recibo por favor" should have good chances of securing you a receipt. Now there is no excuse for getting lost.