Here is one of Google's announcements of ending Street View support for Google Earth versions 5.x and older.
"With the most recent update to Google Earth (6.2), we are also finalizing our transition to a new method of delivering Street View imagery in Google Earth. This means, that the older versions of Google Earth (anything before 6.0) will no longer be able to access Street View. We held off making this change until now, when the vast majority of Google Earth users are on 6.0 (or later)." -- Google Jan 2012.
Basically, Google decided to improve the Street View interfaces which would be implemented in the current versions of Google Earth for desktop and mobile platforms rather than keep supporting the older (less efficient) method of accessing Street View.
by google map or google earth
Not yet for Google Earth. Google recently created historical imagery for Street View on Google Maps. If historical imagery is available then a clock and date will be displayed in the upper left of the map.
Street View, google's high-res panoramic view, can be enabled in Google Earth v6 by dragging the orange "pegman" icon (found near the navigation controls) onto the map.
Google usually never gives out its schedule when a given country will be added to Street View until its well underway. Google Street View was recently introduced to a number of Latin American countries -- see related links below.
The Street View "pegman" icon disappears from the Google Earth navigation controls when your zoomed out at an eye altitude of about 350-500 miles or more above ground level. The Street View mode only makes sense when you're "close" to the city or street-level. At the state or country zoom-level the Street View mode would have to show too many areas that are street-view capable so Google requires the user to be closer to the ground before Street View is allowed.
Google Street View is a technology featured in Google Maps and Google Earth launched in 2007.
Google Maps from the web browser and Google Earth from the desktop can view Street View. you can also view traffic.
In Google Earth v6 you drag the new orange "pegman" icon (found near the navigation controls) onto the map to enter Street View. As of Jan 2012 Google has discontinued Street View support in Google Earth 5.2 and earlier.
by google map or google earth
When Google updates it street view photos in its image database then these updates are made available to Google Maps and Google Earth.
on Google earth but you have to download it first
Not yet for Google Earth. Google recently created historical imagery for Street View on Google Maps. If historical imagery is available then a clock and date will be displayed in the upper left of the map.
To compile Google Earth street view photos, Google send out vans with panoramic cameras. Because it was and is an huge task, some images are not up to date, but it is an ongoing process.
You can, but it is a rather new functionality added to Google Maps / Google Earth, and at the moment, the street view is only available for major avenues and roads.
Street View, google's high-res panoramic view, can be enabled in Google Earth v6 by dragging the orange "pegman" icon (found near the navigation controls) onto the map.
In the redesign of Street View in Google Earth 6.0 the zoom capability found in the previous version was removed. A number of users have asked for this feature back so stay tuned to see if it appears in the next version. Google Earth 6.2 has brought back a zoom feature in Street View using the mouse scrool-wheel to zoom in/out. Google Maps has a zoom feature in Street View as well as other features (e.g. 3D mode) not found in Google Earth.
In Google Earth or Google Maps you can enter your address and start viewing your neighborhood. In both you can see high-resolution photographs in Street View. Google Earth is an application you can download for free and Google Maps is a web-based map. See related links.