As promised, PS3 firmware 2.36 is live. This is a precursor to the very desirable firmware 2.40, which will include in-game XMB. Firmware 2.36, on the other hand, will only improve "system stability when playing select PlayStation format software titles." That's better than nothing, right?
In order to access the PSN, this firmware update is required. For everyone else, you can just wait for the big 2.40 update.