Hi Sarah-
You want to use the "Resamp" "ULay" button in the "Define Datamode" pane on the AFNI controller. The process is described in a bit more detail in handout # 10 on Volume Registration/Talairach Transformation (http://afni.nimh.nih.gov/afni/doc/edu/afni10_volreg_talairach)
Cheers,
Josh
---------------------------------
Josh Powell
Research Associate
Center for Health Behavior Neuroscience
University of Kansas Medical Center
jpowell <two> <at> kumc <dot> edu