As the English and American school systems are a source of endless confusion to me and my Scots educated brethren, I thought I would post a simple outline of the Scottish system to clarify it in the minds of others.
Compulsary education begins at Nursery school from the age of four. This is a half day session with a nursery teacher and one or more nursery nurses, held either at a private nursery (with public funding) or at a nursery attached to a primary school.
Nursery school is followed by seven years of primary education, each year being called "Primary 1", "Primary 2" etc. During this time there are no formal examinations or standards required to progress to the next year, but there are standard tests to judge a school's effectiveness and place in in a league table. Typically, primary school classes will be between twenty and thirty pupils in size, though some small schools or private schools may have much lower class sizes (I was in a class of exactly one during primary five, the school had thirteen pupils). Most classes are taught exclusively by one teacher, only music and PE have specialist subject teachers.
Secondary school in Scotland typically lasts for five or six years, with compulsary attendance until age sixteen. The main difference from Primary school is the introduction of subject teachers - usually every subject will be taught by a different teacher. Class make up varies from school to school, but in most cases the first two years are spent taking a generic mix of subjects with the same class of pupils for each subject. In third year, pupils choose between 6 and 8 subjects for the Standard Grade examinations (the lowest of the three grades of Scottish examination). This neccessitates having different classes for each lesson, you will no longer be able to sit next to the same person in each class. Standard Grades are sat in fourth year, at which point (if a pupil is continuing in their education) four to six subjects are chosen for Higher Grade examinations which are sat the following year. In sixth year, pupils generally either resit examinations they performed poorly in, take additional Higher or Standard grades to get into University or sit one or more Higher Still examinations.
There are three classes of examination in the Scottish system. The first are standard grades, these are taken in fourth year and generally seven are sat by each pupil. A student can be presented at either credit/general level or general/foundation level. This dictates which papers he will sit, two from credit/general/foundation. Each paper can be awarded one of two grades, meaning if you sit credit/general you can be awarded with a 1 (for a good pass in credit), a 2 (a poor pass in credit), a 3 (for a good pass in general) or a 4 (a poor pass in general). Foundation papers will get you either a 5 or a 6 and a 7 is awarded for failing all papers. This exam is rougly the equivalent of a GCSE or O-level exam.
The next level of examination is the Higher Grade exam. Pupils sit about five of these in their fifth year of secondary school. It is a higher standard than Standard grade, but it is considered to be easier than the equivalent A-level. Each subject has one or more papers, as well as certain coursework elements. Everyone sits the same papers with no Credit/Foundation split. Grades awarded are the traditional A-D + F (like the rest of the civilised world). The higher grade exam forms the main part of the qualifications for University.
In sixth year there is the opportunity to sit Higher Still exams in any of the subjects that have been taken at Higher grade. This brings the qualification parity with A-levels by adding another year of study. They are used to gain entry into English University courses and over subscribed Scottish courses.
University in Scotland follows the same system as English Universities, however, there is one important difference. In England, all courses are by default "honours" courses and last three years - in Scotland, the three years results in the awarding of an "ordinary" degree, one extra year is required for honours, resulting in a course length of four years for an equivalent qualification to an English degree. Another difference is that since Scotland got its own parliament tuition fees have been abolished north of the border, making it £3000 cheaper to get a degree in Scotland than in England.