For those you who are Call of Cthulhu novices, I suggest you stop by the Chaosium website and grab a copy of Quick-Start Cthulhu (URL below, since the forum software doesn't seem willing to attach a link to the text). I've run my haunted house scenario for veterans and novices alike, so there should be no problem accepting anyone. I am aiming for six to eight players for the game, but have twelve pre-gen characters just in case.
~ http://www.chaosium.com/forms/coc_quick_start_color.pdf