Mapping Article
have posted an article which features a bunch of famous level designers top tips for level designing, among the people sharing their tips are, Greg Barr (mapper on the Soldier of Fortune team), Steve Cotton (co-lead artist on Rainbow 6: Rogue Spear), Teemu Heinilehto (texture artist on the upcoming Max Payne), Rich, aka "Holy Goat" (mapper on the popular Action Half-Life mod) and Aki Maatta (mapper on Max Payne).