Use the "editedon" property of the document to get the unix timestamp, then use the PHx plugin and placeholder [+editedon:date="format"+] to format the output.
andrazk: tnx for your reply but as you suggest i guess this is for the document itself currently outputted.
I think I was not clear sorry but what I want is a last change date in general, saying "the site
was last updated at: 19-02-2007 00:18" where the date and time is the date and time of the last
changed document. This will be shown in a footer on every page.
yeeeeaaaahhhhhh exactly what i wanted THANK YOU very much andrazk