Several tourism projects in northwestern Namibia support San communities, including the Nyae Nyae Conservancy and Tsumkwe Lodge. Communities who participate in tourism have benefited over the years as they are able to maintain their lands, support themselves and avoid encroachment from farmland. There is still much prejudice towards the San and their supposedly "primitive" culture, but successful tourism initiatives are starting to shift this opinion, as their value is recognised.
However, badly managed tourism is even more damaging than no tourism. Before booking a tour with the San, ask some questions of your operator: How much involvement does the community have in the tours? How are they compensated? Does your guide speak the local language? Does tourism support community projects?
Above all, ensure that your visit is not a one-way experience. Ask your hosts questions - and invite them to ask you questions back. Interact, rather than just standing behind your camera. This is not only respectful to the community; it's also guaranteed to give you a much more memorable trip.