The timeline for GSoc is actually quite tight:

• March 9: Mentoring organizations can begin submitting applications to Google
• March 13: Mentoring organization application deadline
• March 13-17: Google program administrators review organization applications
• March 18: List of accepted mentoring organizations is announced
• March 18-23: Would-be student participants discuss application ideas with mentoring organizations.
• March 23: Student application period opens
• April 3: Student application deadline 5:00 PM PDT/00:00 UTC April 1, 2009
• Interim Period: Mentoring organizations review and rank student proposals
• April 15: All mentors must be signed up and all student proposals matched with a mentor
• April 20: accepted student proposals are announced
• Community Bonding Period: students get to know mentors, read documentation, get up to speed to begin working on their projects
• May 23: Students begin coding for their GSoC projects, Google begins issuing initial student payments
• Interim Period: Mentors give students a helping hand and guidance on their projects
• July 6: Mentors and students can begin submitting mid-term evaluations
• July 13: Mid-term evaluations deadline, Google begins issuing mid-term student payments
• Interim Period: Mentors give students a helping hand and guidance on their projects
• August 10: Suggested 'pencils down' date. Take a week to scrub code, write tests, improve documentation, etc.
• August 17: Firm 'pencils down' date. Mentors, students and organization administrators can begin submitting final evaluations to Google
• August 24: Final evaluation deadline, Google begins issuing student and mentoring organization payments
• August 25: Final results of GSoC 2009 announced
• September 3: Students can begin submitting required code samples to Google
• October, date TBD: Mentor Summit at Google: Representatives from each successfully participating organization are invited to Google to greet, collaborate and code. Mission for the weekend: make the program even better, have fun and make new friends

(source: http://socghop.appspot.com/document/show/program/google/gsoc2009/timeline)