Looks like Google Apps has made the free/standard version harder to find. If you search for “google apps” in Google, you get pointed to www.google.com/apps/ but that does not have the link to the free/standard version.
As of 9/28/2009, the link to the Free/Standard version of Google Apps is:
www.google.com/apps/intl/en/group/
or
www.google.com/a/cpanel/domain/new
or
www.google.com/a/ and then click on the “Standard” link
Useful, Informative, Interesting