All of Google's branded features are protected by applicable trademark, copyright and other intellectual property laws. Depending on how and what feature you would like to reuse in your work, permission may need to be sought from Google first.
An overview of guidelines relating to specific Google services can be found at: http://www.google.co.uk/permissions/
Google Maps/Google Earth Terms and conditions can be found at: http://www.google.com/intl/en-US/help/terms_maps.html
Google Maps/Google Earth allows the user to rely on the principles of fair use for a lot of its content though this exception is unlikely to be applied to commercial work, marketing or promotional material.
"Fair use is a concept under copyright law in the US that, generally speaking, permits you to use a copyrighted work in certain ways without obtaining a licence from the copyright holder. There are a variety of factors that affect whether your use of Content would be considered fair use, including the purpose and character of your use, the nature of the copyrighted work, the amount of the copyrighted material used and the effect of your use upon the potential market for the copyrighted work. For example, there are differences between use in a for-fee service and use in a work of scholarship, or the use of a single map screenshot and the use of detailed map images for an entire country. There are similar, although generally more limited, concepts in other countries' copyright laws, including a concept known as "fair dealing" in a number of countries. That all being said...
Please do not request that we interpret whether your use of Content is fair use. Google cannot tell you if your use of Content from our products would be fair use or would be considered fair dealing; these are legal analyses that depend on all of the specific facts of your proposed use. We suggest that you speak with a lawyer if you have questions regarding fair use of copyrighted works."
Google Maps/Google Earth attribution guidelines are available here: http://www.google.co.uk/permissions/geoguidelines/attr-guide.html
"All uses of Google Maps and Google Earth Content must provide attribution to both Google and our data providers. We do not approve of any use of content without proper attribution, in any circumstance. We require attribution when the Content is shown. Requests for exceptions will not be answered or granted."