When I use the following line in my process (my process run these line
each 10 seconds), memory size increases progressively :
myDate = datetime.datetime(*(time.strptime(dateString,
"%Y-%m-%dT%H:%M:%S")[0:6]))

the '*' operator unpacks the tuple, producing the argument list for
datetime.datetime but it seems that the structure return by
time.strptime is not correctly flushed in memory.

Can you reproduce this with a script that does nothing more
than

while True:
  myDate = datetime.datetime(*(time.strptime("2008-12-10T14:00:03",
"%Y-%m-%dT%H:%M:%S")[:6]))

I tried with both Python 2.4.5 on Solaris and Python built from
CVS (aka 2.7a0) on my Mac and see no memory growth of the
processes.  If there's a memory leak my guess is that it is
somewhere else.

Tried it with Python 2.5.2 on WinXP, I see no memory growth either.

After running for more than 2 hours, I could not see any memory growth 
with 2.5.2 on WinXP.

A number of people on a number of platforms and versions can't reproduce
this.