Klicek is a Polish 3D artist who just did this really ground breaking, easy to follow Zbrush modeling tutorials.
There is only one catch - they're in Polish. But hey - who said we are going to do it easy way? 

Now, here's codec that You will need: 
http://www.free-codecs.com/Real_Alternative_download.htm


So far there is 8 tutorials and they are respectively:

lesson1 - Zbrush interface (You don't know Polish? Leave it)

lesson2 - How to do a base mesh using a Z-spheres

lesson3 - How to do base mesh using Wings3D (http://www.wings3d.com/)

lesson4 - All you need to know to start creating bump maps and displacement maps

lesson5 - How to map models and jump between 3ds max and Zbrush

lesson6 - Here is starting a REAL DEAL - even if you're not Polish you'll get a lot from it. Alien modeling session started, lets see how to do brilliant lips easy way!

lesson7 - Keep working on Alien! Now lets see how detailed eyes are to be modeled easy way too!

lesson8 - Our Alien head is taking a nice shape - plus we will give him some nostrils to take a deep breath!

Now that's about it - SEED IT!
News about whats going to be next you can find in that thread: 
http://www.max3d.pl/forum/showthread.php?t=35770
(Polish again lol - but You can ask there in english - probably someone knows that language :P Me in example :/)