Chris Caldwell (caldwell@utm.edu) maintains a list called "The Largest Known Primes." Some of the ways to get this list are:
    web:     http://www.utm.edu/research/primes/largest.html
    gopher:  unix1.utm.edu, directory 1/user/Public_FTP/pub/math/primes
    ftp:     math.utm.edu, directory /pub/math/primes
   Finger primes@math.utm.edu for a few record primes and the current
   ways to get the lists.  He would like to know of any new titanic
   primes (over 1000 digits) so that he can add them to his list.