When you say "seconds only" do you mean it need not display tenths of a second or that it must display seconds and not Mins + Seconds?

I know there are ounters that count in mins & seconds. Even versions that speak the time as they go.

If you need to make one the best way would be to use a counter module

http://www.maplin.co.uk/module.aspx?ModuleNo=3279&doy=1m7

and feed it with 1Hz from a simple oscillator. That Maplin part has an onboard 512Hz oscillator so you could just divide that by 512 and feed it back in to the counter input. Devices like the HC4040 will do the divider for you but you might look for a way to do this without needing another supply rail (the module uses 1.5V).

You would need to think about the reset so that you don't loose part of the first second if you see that I mean.

How accurate do you need?

Yet another edit...

That maplin part above has been discontinued but another possible source here..
http://www.mutr.co.uk/prodDetail.aspx?prodID=802