Here is a great tutorial for the pen tool:
http://www.thegoldenmean.com/technique/pen1.html
and I QUOTE from this source:
Quote:
I hope to shed some light on the Pen Tool and dispel some of the myth because this really is an industrial strength power tool. I’ll admit that when I’m evaluating a fresh–eyed art school graduate who struggles to make a selection with the Magic Wand when the Pen Tool could do the job better in a fraction of the time, it just screams to me — “no real–world experience!”. Get friendly with this tool.
...the pen tool is unsurpassed for two things: precise, sharp edged selections, and Clipping Paths.
Another educational source for all kinds of selection methods, including pen tool and masking:
Katrin Eismann's Photoshop Masking and Compositing - outstanding book. Chapter four is devoted to the pen tool
www.photoshopmasking.com