According to VG247, a "prominent PS3 developer" said that firmware 2.70 will go live this week. The unnamed developer made the assertion during GDC. The dev also said that developers got the update yesterday. The update also supposedly went live for a brief time, before Sony pulled it down. The release of Firmware 2.70 hasn’t been confirmed by Sony yet, so you should hold off until an official announcement is made. We speculate that the new firmware will likely be release tomorrow when the new Resistance 2 patch goes live.
The new Resistance 2 patch will let a second local player to log in using his own PSN profile and save his progress. Insomniac devs have stated before that this needed a firmware feature not available during the game’s launch, so the fact that they’ve already managed to implement it is a good indication that Firmware 2.70 will launch tomorrow.