Sony's Director of PlayStation Network Operations Eric Lempel has announced that PlayStation 3 Firmware update 3.01 is now available (not a mandatory update) and fixes the reported 3.00 update issues, as follows:

Hi everyone, PS3 system software update 3.01 is now available for download. This is an optional update that improves system stability during use of some PlayStation 3 format software.

After playing through some of Uncharted and clearing a previous freezing point, the game is running smoothly again. Do be sure to check any of your own titles that you had a problem with and see if they are running fine. Other than that, it looks like Sony fixed the 3.00 issues.

To quote Eric Lempel's PS Blog reply on the changes: "Yes, this will fix the issues that some users have experienced with Uncharted: Drake’s Fortune."