The deadline for the submission of new sites for the November release of the TOP500 List is October 20th (23:59 PST). All system reported have to be installed by October 27th. The last date for submitting Linpack updates is also October 27th (Systems must have been submitted by the deadline above).
Submission deadline for the June release of the TOP500 List is May 5th (23:59 PST). All system reported have to be installed by May 12th. The last date for submitting Linpack updates is also May 12th. (Initial submission (placeholder) must have been completed by May 5th)
The interface for submitting new systems is http://top500.org/submit