Panel Study of Income Dynamics (PSID)
------------------------------
http://www.isr.umich.edu/src/psid/  ## Homepage
http://simba.isr.umich.edu/  ## PSID Data Center.  You can create subsets of many PSID datafiles.
ftp://ftp.isr.umich.edu/pub/src/psid/main/  ## Main 
ftp://ftp.isr.umich.edu/pub/src/psid/supplemental/  ## Supplemental

Note:  The Cross-National Equivalent File (CNEF) contains equivalently-defined
variables from the PSID and the German Socio Economic Panel (GSOEP), the British
Household Panel Study (BHPS), and the Canadian Survey of Labour and Income Dynamics
(SLID).  Please visit  http://www.human.cornell.edu/pam/gsoep/equivfil.cfm

(Note from a user about the PSID):
PS. There's one very minor mistake in their manual, which would be worth
alerting NBER users to if you put it on the site. They say at the top
of p.59 of Vol II of the PSID manual that the state geo-codes use the
NBER coding system. Actually, they use the PSID coding system. This
doesn't seem to affect the accuracy of anything else, though -- the value
labels are correct, and the state tax rates all seem to line up.