Update:
As mentioned in more recent answers, since Django 1.2 you can use the exists() method instead (link).
Original Answer:
Dont’ use len() on the result, you should use People.objects.filter(Name="Fred").count(). According to the django documentation,
count() performs a SELECT COUNT(*)
behind the scenes, so you should
always use count() rather than loading
all of the record into Python objects
and calling len() on the result
(unless you need to load the objects
into memory anyway, in which case
len() will be faster).
source: Django docs