If you found that your R (resource) generated class in Android project have errors you will want to force Eclipse to rebuild that class. To force Eclipse to rebuild generated resource class (R), you just need to click on Project->Clean menu, and then select which projects you want to clean.
In my case rebuilding generated class did not helped because there was error in my XML layout file and class again had the same error. So if you ever have error in your R (resource) generated class, it is better to first check your error log and find where in the layout or resource files you have error. Usual error is wrongly named resource id of control. After you fix that error and save changes error in R class will usually disappear.
Have you realized the importance of ListView control in developing android applications ?
Script for creating Android icons for different screen resolutions at once. Icons can be saved using standard Android icons naming conventions and saved in appropriate folders.
Source code with examples how to use relative layout to create nice buttons with text and images in Android
Tutorial about connecting to the web pages on the Internet from Android application, using both POST and GET web requests.