Contrary to Richard's post, GCSE exam timetables for summer 2010 have been available for some time. You'll need to know the name of the examining body (such as AQA, OCR, etc), together with the subjects being taken (and, where appropriate, which syllabus option the school uses and/or the level of entry).
Go here and click 'Accept':
http://www.modernisat...org.uk/comptimetable/
Set 'Session/Year' to 'Summer 2010' and 'Qualification' to 'GCSE'. Select the relevant examining body. (If in doubt, select 'All'). Click 'Show All Available Subjects'. Then click on the initial letter of the subject, followed by the subject itself.
When viewing the results, check to see if there's a 'Next' link underneath the list of dates. If there is it means that there are more examinations to be shown. If you fail to click that link you could be misled into believing that the exams finish earlier than they actually do.
I used to teach GCSE maths. The final maths paper was often the last exam for most candidates. In 2010 the date of the last maths paper (for most syllabuses and exam boards) is Monday 21 June.
Chris