I would add that comprehensive icons are always better: takes less room, does not need to be read, give consistency between application. when using icons, be sure to be coherent, and to use well known metaphors.
The main function of Tabs is to move between different views. Tab is one of the basic element for User interface in Symbian.
This article describes general and simple rules that should be kept in mind during designing tabs in your application. The rules are very well-explained with image implementations. This article is specially meant for beginners. Beginners can also refer Custom tabs to make the tabs more attractive in their application.