Is there any new cockpit that uses voice commands (think for example Siri from the new iphones) that can identify the voice of the pilot and help him/her to fly?
There was a product by a company called VoiceFlight which would allow you to program Garmin GPS systems (GNS 430/530), which was FAA-approved by STC for a good number of light General Aviation aircraft.
While it was not capable of flying the plane by voice instruction it could be used to program a route into the GPS, which a coupled autopilot would then be able to fly.
The VoiceFlight product has been discontinued as competition from the newer GTN 650/750 (which require less knob-twiddling to program a route) and other technologies like Connected Panel ate into the company's business to the point where it was no longer viable to remain in business, but the core idea of voice technology in the cockpit has been proven possible (and according folks who tried it, even practical). It may make another appearance some day.
No, voice recognition is currently not used in aircraft as it would have to be built into the aircraft to pass certification for the aircraft and with rotating crews on aircraft, the voice recognition would need to be able to work with too many different voice types: high pitch, low pitch, male, female, accents, dialects and many more factors.
Voice recognition works because it learns from the user over time, something that is not possible in a cockpit environment with crew resource management.
There is a prototype in development by Honeywell at the moment, but it's in early stages of development.
Related reading: The benefits of a Speech Recognition enabled cockpit by AdacelPDF
Yes - Typhoon uses a "Direct Voice Input" (DVI) system. This has a limited vocabulary which allows the pilot to control non-safety critical items via voice input. The current system uses an uploaded template specific to the pilot to enable recognition. Although developments are looking at various updates including removing the dependency on pilot templates.