find and replace content

Hi all,

Just started with PHP and Postgres last week. I have a bunch of
pages that bring in different content depending on the page. Now
I need to change a name that appears in the content throughout
these pages. Is there a way to do a find and replace throughout
the database searching the content? I want to do something like
replace all occurences of Jones with Johnson.

Can I do this directly or do I need to write a simple php page to
do this? I know this sounds simple and the solution probably is
too, but after hours of searching I still cannot find it.

Thanks in advance,
/mark