@Simonsky, follow up with the HR lady or hiring manager. Ask if the position has been filled, and if not, if you're still being considered for the position or not. Also, make sure you keep applying and interviewing with other companies.As to response time, with large corporations it can take weeks to hear back, so i echo the "don't get too down yet" thought.
My wife is a tech/finance headhunter for companies all over Southeast Asia and I've been interviewing and hiring programmers since the 90's. Hit me up if you need advice.