Kirklees YPS have produced some policy guidance for use of Facebook by staff for work purposes and a manual to set up suitabley configured accounts, but you can consider the points raised for any social networking situation
Facebook and YPS Guidance Notes Facebook Manual
YHGFL have created a guide for Facebook use by staff (revised for SID11) and a guide to Facebook Privacy settings,
Safe use of Facebook by staff Facebook privacy settings
and SWGFL have also produced a guidance leaflet
SWGFL Facebook advice (see also link)
The same principles and issues should be considered for all social networking sites as should those raised on Chatdanger that are aimed at children
Chatdanger
Childnets Digizen has a extensive general guide to on social networking site evaluation and use, and the EU have launched their own advice for site developers and operators
Digizen EU Safer Social networking principles and evaluation
You might also be interested in OFCOM’S latest analysis and DCSF report on positive used of technology by young people
Social networking report Safe and Effective SNS Applications
It is also pertinent to consider how DCSF Guidance for safer working practice for adults who work with children and young people should be applied in the context of SNS, as it covers areas of communications and use of photography and video.
There are also additional references to the use of social networks for youth engagement compiled by English National Youth Arts Project.
The advice of ICO on gaining permission before using photographs may also be relvent reference as might local article on Geotagging and confiscation