Rasta’s -Tutorials can be found hereD
Topo-Tutorials:
http://www.zbrushcentral.com/zbc/showthread.php?t=46117
http://www.zbrushcentral.com/zbc/showthread.php?t=48689
ZProject-Brush:
http://www.zbrushcentral.com/zbc/showthread.php?t=46544
Merging Objects:
http://www.zbrushcentral.com/zbc/showthread.php?t=47410
Pipeline ZBrush to C4D (German language):
http://www.zbrushcentral.com/zbc/showpost.php?p=352966&postcount=18
A very quick & high quality alternative to Displacement & Normal Maps :
http://www.zbrushcentral.com/zbc/showthread.php?p=457194#post457194
Easy create own materials
http://www.zbrushcentral.com/showthread.php?p=673343