As announced earlier, the PC patch for New Vegas is up on Steam now, and will update automatically. Updates for Xbox 360 will come in later, as well as updates for PS3 whenever they fix PSN. The patch notes do not add anything to the earlier list, so the "optimizations and stability improvements" will remain unknown.
Addendum: For PS3 users, Jason Bergman adds.<blockquote>I'm told game updates may be functional over PSN, despite the outage (system updates are). If so, the FNV patch will be live at 00:00 GMT.</blockquote>Addendum 2: Ausir notes the PS3 version is up, at least in the SCEA area (North and South America).
Addendum: For PS3 users, Jason Bergman adds.<blockquote>I'm told game updates may be functional over PSN, despite the outage (system updates are). If so, the FNV patch will be live at 00:00 GMT.</blockquote>Addendum 2: Ausir notes the PS3 version is up, at least in the SCEA area (North and South America).