Mentoring teacher Programs

Knoxville High School has recently started a mentor teacher program. Although it has a good purpose at heart, teachers have expressed concerns that the program is not reaching the needs of the beginning teachers. The main complaint seems to be a lack of time at school to meet with one another. Our principal has tried to address this by placing the teachers with a mentor whose room is in close proximity. This has opened up the communication lines, however it has not evolved into the formal mentoring program we wished it to become. What have other schools done to aid their programs? What are the main problems you have encountered?