Here's a good way to ask over the phone: Hello MX, I would like to thank you for taking the time to interview me for the xxxxx position last week. Also, I was wondering if you could tell me the status of my application.
Leave a voicemail message if you can't talk to person.
In a thank-you note by email, I would say something to further express your interest in the position. The email shouldn't be too long - just two short paragrahs or a few sentences.