Selling pictures - what are release forms?

[ehasler]

If I take a photo that contains a recognisable building or person(s) and wish to sell it, does anyone know what sort of permission I need to obtain?

I've heard of building and model release forms, but don't know exactly what these are, when they are needed, and whether you need to get these at the time you take the picture, or if they can be obtained at a later date.

Has anyone had experience of this before?

[leszekg]

There is plenty of advice and sample release forms on the well known photographic web sites. Just do a search on 'model release forms'. One good example is:

<www.ephotozine.com/freelance/fullstory.cfm?freelanceid=16>