Gnome file permissions

[Neo]

On a folder how can I set the permission on that folder and all items
within that folder.

E.G. I have a directory that is set to read only and in that directory
there are loads of files and other directories with the same
permissions. I want all these to be changed in one easy step via a gui.
Right clicking seems to only change the highligted items. I cant see an
option to say and all other items.

all help would be great

Neo