Accomodation in Oslo

More of a hotel than a Bed and Breakfast, but because it's the only place I know in Oslo, I'll recommend Hotel Continental. Although not exactly cheap (this is Norway, after all!), it offers really good value for the quality and you can't beat the location. I don't know if you'll have the opportunity to interact with "locals" (why would someone who lives in Oslo stay in a hotel there?.. well, unless the hotel charged hourly rates...), but you'll have good chances to talk it up with other travelers from around the world.

Thanks...I'll take a look at the Continental.

A few years ago I stayed at Cochspensionet (from Rick's guide). It's not really a B&B, but you can cook in your room. The rates are a lot cheaper than any hotel in Norway. It is located on the northwest side of the palace park, and you can walk through there to get to the main shopping area (Karl Johanns Gade). There are streetcar lines close to the pension, too. As for meeting the locals over meals, there is a small chain of restaurants in Oslo, called Cafe Odom. There were four of them, scattered along Karl Johanns Gade when I was last there. Seating was open and after you selected/paid for your meal you were given a numbered sign to put at your seat for the server to find. I found my fellow diners to be open to general conversation. There are a number of eating places for students near the university and bookstores there, and again I found people to be reasonably friendly. The fact that you are a self-guiding traveler can be a good conversation starter as soon as someone hears your accent.

Thanks very much for the suggestions! I'll give the hotel a look. We've been looking at flats through AirBnB, but I'm continuing to look to see where I can find the best deal. We'll keep an eye out for the restaurants as well.