There is the Mathematics Jobs Wiki:

http://notable.math.ucdavis.edu/wiki/Mathematics\_Jobs_Wiki

It is a wiki, so what is listed there is dependent on people bothering to put stuff up.  It is trying to be international in scope -- in fact, the only jobs that seem to be listed on it at the moment are from Germany.  

Also, for Canada: http://www.cms.math.ca/Employment/