1. In Eclipse, from the menu, click File, the Import...
2. Expand the Android folder, and select Existing Android Code Into Workspace, and click Next.
3. Click the Browse button, then navigate to your Android SDK folder and find the library you wish to import. For example, to import Google Play services you'd choose the google_play_services folder, then click OK.
..\sdk\extras\google\google_play_services
4. Then click Finish to import it.
Resources:
http://code.tutsplus.com/tutorials/integrating-google-play-services-on-android--cms-19828
