My suggestion would be to use a combination of scripts that can check for possibly offensive language as well as people who can check things as well. What is offensive to one, might not be offensive to another. You might take a look at how the
message boards are handled. There are moderators who are regular users but have been around long enough to have a good feel for the particular community. They use a standard along the lines of "would you want your (hypothetical) 14-year old sister to read/hear this?" It seems to work reasonably well (or did when I was regularly posting there). You might want to start with a very restrictive policy and then ease up on it as the community develops. Also, I'd say let the community that develops decide how best to police itself.