Originally Posted by J.P.

try using this:

/\{\$[^\}]+\}/


BTW:
"greedy regexp" does not have anything to do with multiple matches...

if you would use /\{\$.*\}/ on "hello {$site} and a happy new {$what}"

greedy regexp would match a "{$site} and a happy new {$what}" and the non-greedy one would match a "{$site}" and "{$what}"