Date Questions

It appears to me that there is some inconsistency in the date
calculations for my PostgreSQL install (version 8.0 on Win32).

January 07 of 2007 is a Sunday. Based on the documentation I would
expect that date to be the first day of the second week of the year
2007. That's not what I'm getting. When I run:

select date_part('DOW'::text, '2007-01-07'::timestamp);

I receive my expected result of 0 indicating that Sunday is the first
day of the week. But, when I run

select date_part('week'::text, '2007-01-07'::timestamp);

I get a result of 1 indicating that it is part of the first week of the
year. That seems inconsistent with the first result which would indicate
it was the first day of the second week of the year. I was expecting a
result of 2.

Am I missing something?

Many thanks!

rjsjr