The average salary for a Microsoft Certified Technology Specialist on Windows Server 2008 is �35,000. This is based on data from the summer of 2010 in the UK.
Remember that salaries vary depending on country and location. The highest paid jobs for MCTS Server 2008 are offering up to �53,000 per anum. This is roughly $80,000 a year. The actual average salaries have declined in the last year or so because of the financial problems. In 2009 the same role would have offered �57,000!
Research shows that as a new technology is released, the demand for the skill is so high and the number of professionals with those skills is low, hence the salary is much higher. As time progresses and people acquire the skills the salary drops because the supply is higher. Check out Wikipedia supply and demand model for more details on economics.
In the UK, an MCTS qualified individual would find the highest salary in the South East of the country, mainly in London. This is usually the case, with most big companies being based in the capital.