Your program needs to inform its people about the type of behavior it expects of those using the internet in the workplace and about the consequences for abusing internet privileges.
Areas to Consider
Monitoring: Are you going to be monitoring or filtering traffic in and out of the network? If you are people need to know that and if you aren't people need to know that their movements are probably still being logged by your firewall and your ISP and that the workstation they are using will keep track of sites and images they have viewed.
Prohibited Use: Most legal aid programs related that the primary purpose of internet access for their employees is for program related work and that they specifically prohibit things like: obscene materials, gambling, LSC restricted activity, prohibited file sharing (i.e. Kaaza or bittorrent), instant messaging and for-profit use. Some programs prohibit all non-work related use.
Personal Use: Some allow personal use on non-work time except for specifically prohibited activities.
Acceptable Downloads: Over and above prohibited items, folks can load their system up with spyware and potentially damaging viruses and clog up your internet pipeline with large downloads. You can cover this is a security section as well.