This is probably the clearest statement from him on the issue:
http://betaboston.com/news/2014/12/10/audio-peter-thiel-visits-boston-university-to-talk-entrepreneurship-and-backing-zuck/
25:30 mins in
TL;DR: he thinks its an issue but also feels AGI is very distant and hence less worried about it than Musk.
I recommend the rest of the lecture as well, it's a good summary of "Zero to One" and a good QA afterwards.
Context: Elon Musk thinks there's an issue in the 5-7 year timeframe (probably due to talking to Demis Hassabis at Deepmind, I would guess). By that standard I'm also less afraid of AI than Elon Musk, but as Rob Bensinger will shortly be fond of saying, this conflates AGI danger with AGI imminence (a very very common conflation).
The Rob Bensinger post on this is now here.