You can also get to it from the Windows Start Menu by running "Check for Updates" in the Embarcadero RAD Studio XE group.
This update is a combination of three updates - a core product update for Delphi and C++Builder, a documentation update for Delphi and C++Builder, and a Boost Libraries update for C++Builder.
The fix list for Update 1 is available on EDN.
The update will also be available soon on the registered user download pages for Delphi, C++Builder and RAD Studio.
Updated versions of the full installers and ISO should be available to new users, trial downloaders and All-Access customers next week.
If you're one of those people who doesn't like to upgrade to the new version until after the first update is released, your wait is over.