I went to Dosa in the Mission on Wednesday night after volunteering with One Brick at the offices of At The Crossroads (both organizations worthy of your time, by the way).
Dosa was jumping with lots of people milling about outside in the nice evening air on Valencia Street while they waited for seating. Somewhat surprisingly, we only had to wait 15 minutes for a table. The space is attractive, if a bit cramped, done up in deep oranges and browns. There's some interesting Indian artwork adorning the walls.
I am not very adventurous when it comes to Indian food, but I can say that I would absolutely recommend everything I ordered to anyone going there (and would have most of what I had again).
I started with the Chennai Chicken, followed by the Chatni Masala, the Lentil Chicken Curry and, for dessert, the Gulab Jamoon. Check the link above for better descriptions of everything. Definitely a cool experience and great exposure to some tasty South Indian fare.