iOS5 and iCloud available now
Apple has now pushed the iOS5 update to the public. You can now update your iOS firmware via iTunes. Jailbreakers should hold off until the dev-team releases an update to their tools and those who require an unlock should wait until PwnageTool or Sn0wbreeze are updated to allow baseband preservation while updating.
Also, iOS5 public release appears to be identical to the GM release that was seeded to developers a few days ago. This means that the latest Redsn0w can already perform a tethered jailbreak by pointing it at the GM firmware. An Redsn0w 0.9.9b5 should be released some time today which will add the public iOS5 firmware URLs so that you don't need to specify a firmware file.