Public participation is used as a means of considering comments and objections raised by what is often termed 'interested and affected parties' (I&APs). These may consist of national and international NGOs, other commercial interests and members of the general public, any or all of whom may be affected (or think they are affected) by the proposed development.
Methods used to include concerned stakeholders vary a little around the world, but frequently include public meetings, announcements and notices on the site boundary and/or local notice boards, and perhaps also in local newspapers and magazines. Best practice guidelines for public participation can be found on the IAIA website at <http://www.iaia.org/modx/assets/files/SP4%20web.pdf>
The person(s) conducting the impact assessment should ideally be in charge of public participation, as this is the method that will be used for incorporating external views into the IA process. It may be important to have a representative from the intended developer present.
A great deal of very useful information can be found through the EWT EIA toolkit, which is available from <http://www.eiatoolkit.ewt.org.za/> (pdf 64Kb). Although this deals with the issue from a South African perspective, the problems are fairly universal and many of the proposed solutions could be modified to be appropriate across much of the world.