Google Maps for Mobile

Google Maps (for a time named Google Local) is a free web mapping service application and technology provided by Google that powers many map-based services including the Google Maps website, Google Ride Finder and embedded maps on third-party websites via the Google Maps API. It offers street maps, a route planner for bicycles, pedestrians (routes less than 6.2 miles) and cars, and an urban business locator for numerous countries around the world. (Wikipedia)

Features
My Location (beta). My Location shows your current location on the map, usually within 1,000 meters, so that you can find out where you are even without GPS. Google Maps for mobile also supports built-in GPS, or can link to a Bluetooth GPS sensor to more accurately pinpoint a user's location. My Location works by recognizing information broadcast from mobile towers near you.

The My Location feature, available on most phones, also makes it easier to set the start point of your journey.

Map and satellite views. Google Maps for mobile gives you both map and satellite views of the area you're looking at, using an interface that feels just like it does on the desktop. Scroll in a direction to see more of the map, or zoom in and out using shortcut keys.

Google Maps provides high-resolution satellite images for most urban areas in Canada and the United States (including Hawaii, Alaska, Puerto Rico, and the U.S. Virgin Islands) as well as parts of New Zealand, Australia, Egypt, France, Germany, Hong Kong, Hungary, Iran, Iceland, Italy, Ireland, Iraq, Japan, Jordan, Taiwan, the Bahamas, Bermuda, Kuwait, Mexico, the Netherlands, the United Kingdom, and many other countries. Google Maps also covers many cities including Moscow, Istanbul, and most of India.

Business listings. Google's local search engine allows you to search for businesses by name (e.g. "Starbucks"), or by type (e.g. "coffee"). View store hours and ratings, and then dial the business you're interested in with a single click.

Driving directions. It's easy to get turn-by-turn driving directions.

Transit. Check bus and subway schedules, determine what transfers you need to make, and plan adventures in more than 50 cities around the world.

Enter the new version of Google Maps for mobile. This version (2.2) allows you to get transit directions in all the same places as the web version of Google Maps, including Chicago, the San Francisco Bay Area, Seattle, Vancouver, and over 50 other cities in North America.
This version of Google Maps for mobile even has a few tricks not yet available on the desktop version of Google Maps. For instance, you can find the last transit trips of the day (to figure out how late you can stay at the party) and more easily browse through earlier or later trips.

Transit functionality is now available for BlackBerry, Windows Mobile, S60, and other Java-enabled phones.

Traffic. Highways on Google Maps are colored green, yellow or red, based on real-time traffic data.

Favorites. Bookmark your favorite places so that you can easily return to them on the map.

Enterprise installation. IT managers can install Google Maps for mobile on corporate BlackBerry phones through BlackBerry Enterprise Server.

For more information, you can visit http://www.google.com/gmm/
Also, you can download this application for free through http://www.getjar.com/products/15897/GoogleMapsformobile