To get your location you need to press "0" and look for a blue dot on the map.
If you have a GPS-enabled device, this blue dot corresponds to your GPS location. At times, or if you do not have a GPS-enabled phone, you might see the blue dot surrounded by a light blue circle to indicate uncertainty about your location.
Why the uncertainty? The My Location feature takes information broadcast from mobile towers near you to approximate your current location on the map - it's not GPS, but it comes pretty close (approximately 1000m close, on average). We're still in beta, but we're excited to launch this feature and are constantly working to improve our coverage and accuracy.
The My Location feature is available for most web-enabled mobile phones, including Java, BlackBerry, Windows Mobile, and Nokia/Symbian devices.
Go to www.google.com/gmm from a mobile browser to check out the new feature.