Tutorials
There are a number of worked example tutorials on the TalendForge site and these can be found at http://www.talendforge.org/tutorials/menu.php .
There are three easy tutorials that detail some basic techniques, followed by some more detailed, complex examples. Note that some of the tutorials refer to Talend Enterprise Data Integration, which is an enterprise version of the Studio. Although the functionalities are very similar, the enterprise version offers some features that are not available in Talend Open Studio. As a result, there are some tutorials that you will not be able to complete with Talend Open Studio alone.
Additionally, Talend has a channel on YouTube at http://www.youtube.com/user/TalendChannel.
The instructional videos within the channel are really designed for marketing purposes and are not step-by-step tutorials, but, nonetheless, serve as a good introduction to using Talend in different scenarios.