First be sure that the person qualifies for exemption from taxes by consulting
the Treaty Requirments link below.
If they do qualify then they must:
Download and fill out an IRS form 8233 (available
with Adobe Acrobat
Reader)
For up-to-date Treaty Requirements see: http://disbursements-staging.vcbf.berkeley.edu/foreign/
For copy of Tax Treaty Documents go to: http://www.ucop.edu/ucophome/cao/paycoord/taxstate.html