I remember hearing everywhere that babies are not to have whole milk until after their first birthday. Funnily enough, it wasn't just me, but everyone I spoke to that interpreted this as "NO DAIRY". In fact, it is perfectly fine to introduce yogurts and cheeses, although you may want to discuss this with your pediatrician first. When Kyle and I went in for his 9-month check up, and were listing his daily food habits, our doctor said "Oh, you've introduced dairy already?!?" Well... the last time I saw you at 6-months, you didn't say anything about avoiding it!
It was however at a Happy Baby class that I received a handout listing suggested foods to introduce based on age, and saw yogurt listed on there. So I bought plain whole milk yogurt and Kyle LOVED it. He has it for lunch every day now. Soon after that, I was discussing foods with a friend who happens to be a pediatrician, and she suggested trying cottage cheese as her son had loved it. We tried it, and he was OK with it, but definitely not as ecstatic as he was with the yogurt! We'll try it again soon and see if his tastes have changed now that he is used to more texture.
It turns out that it is only whole milk (or any milk) that you aren't supposed to give until 1 year of age. Other dairy is OK, (1) because the lactose in yogurt (cottage cheese, cheese, etc) is already partially digested because of the bacteria and (2) breastmilk (and/or formula) won't be replaced by yogurt and cheeses. I found a good summary on the Wholesome Foods site
In addition to yogurt, Kyle has chunks of mild cheddar as a snack or with dinner nearly every day. I asked my pediatrician-friend if I needed to worry about the 3-day rule when introducing new dairy items, even though I know that he is OK with yogurt. She said that since we have no family history of milk allergy that it should be safe to assume that if he is OK with yogurt that he would be OK with other dairy products.
Other cheeses to look for are colby, jack or american. For the yogurt, I just buy "Mountain High" plain whole milk yogurt, and add a different fruit to it each day. There is also Stoneyfield yogurt that is plain whole milk, or they have their "Yobaby" line, which I don't like because there are too many added sugar and flavors which he doesn't need!