STOC this year is part of the 2003 Federated Computing Research Conference in San Diego in June. Several other theory conferences are also part of FCRC and many of them have deadlines in November or soon thereafter.
My favorite conference, The IEEE Conference on Computational Complexity, will be held in Denmark in July. Their submissions deadline is November 27.
In computer science in general and theoretical computer science in particular, conferences are the primary outlet for announcement and publication of results. Since computer science is a relatively young discipline, the field changes dramatically year to year and the usual long process of journal publications might often publish outdated work. More mature fields like mathematics and physics use journals as the primary source of publication.
The main disadvantage of the computer science system is that while computer scientists are encouraged to submit their work to refereed journals, many of the important papers in the area never make it that far.
There have been at least two recent major exceptions to this process. Alexander Razborov wrote a paper last spring on lower bounds on quantum communication complexity that would have been the best quantum paper in FOCS if not the best paper. Instead he chose to submit it directly to a journal, Izvestiya of the Russian Academy of Science: Mathematics. The Agrawal-Kayal-Saxena Primality Paper which would easily be the best paper at the upcoming STOC is not being submitted to a conference either but directly to Annals of Mathematics. "Why should I send it to a conference," Manindra Agrawal asks, "when everyone already knows the result?"
Are these two papers a trend? Are conferences less important as papers are easily available online? Or is computer science finally becoming a mature field?