Hi, Now that the official GSoC site is accepting student proposals, students should send their proposals to http://www.google-melange.com/gsoc/org/google/gsoc2011/phpmyadmin for them to be officially examined.
In the past, a proposal could be edited by the student after submission and I believe it's still the case. Mentors will interact with students in private to ask clarifications about their proposals.
Discussion may still happen on this mailing list and I'll try today to answer students who previously sent questions about an idea for which I am a proposed mentor.