Small typo fixes and rewrites
Small typo fixes and rewrites

arokem/nipy.github.com,vsoch/nipy.github.com,vsoch/nipy.github.com,arokem/nipy.github.com,vsoch/nipy.github.com,lesteve/nipy.github.com,lesteve/nipy.github.com,lesteve/nipy.github.com,vsoch/nipy.github.com,arokem/nipy.github.com