We're at 246 Brixton Road SW9 6AQ, only a short 10 minute walk from Brixton or Stockwell stations. Transport for London list it as 14 minutes but we've walked it and they must mean a slow walk because it's hard to take more than 10. Perhaps they expect people to go sightseeing on the way.
If you're using the tube, it's probably best to get off at Brixton and walk up the Brixton Road - or use buses 3, 59, 133, 159 or 415 for a couple of stops.
If you're coming from further afield please use the TFL Journey Planner on the left. For the really keen this includes links from all the major train stations and London airports. ;-)