I found my roommates on Craigslist when I moved to San Francisco. I just looked in the Rooms/Shared section under Housing.
My first place was alright. We all were University students and stuck to ourselves, we never really hung out with each other, due to not having much in common.
The second place I found on CL was my favorite though. I moved in with 3 Thai people. My roommate was gay, and super funny and nice. He would cook me breakfast all the time. My other roommate was straight and cool, and would always offer me beer. And my other roommate was an older woman, who would clean the apartment, and once a week would cook the whole house dinner (curry, soup, Korean BBQ, even crab!). It was amazing! One of the best living situations I've been in, but I had to leave when the older woman's niece wanted to move in. She was so nice I had to say yes.
After that I found a place on CL with two straight Indian people. They were really nice, and one would cook me chai in the morning, which was so delicious, and the other would sometimes cook dinner, which wasn't bad. We never really hung out, but got along well.
I suppose you might get lucky too and meet some really cool people. You can even do a search, and find someone posting a room mentioning that they are LGBT friendly, which is nice. When you're seeing the place, ask a lot of questions about what they do for fun, if they're home a lot, if they cook, etc. If when you're seeing the place, they're really nice to you, make some jokes, laugh, and make you feel like you're at home already, that's the place you want to live.
As far as other places you can find on the internet, you might have luck looking at university websites, sometimes they offer free postings of housing, that is offcampus, and technically you don't even have to be a student. Anyway, good luck!