HSMP - Highly skilled migrant Programme. This program allows skilled people to migrate to the United Kingdom having a fully functional working visa. The main advantage of this program comparing for example to WP, is that you are not bounded to some specific employer. Instead you have the full freedom of looking the one you like or changing the current any time you want. You can apply for medical insurance, bank account, driver's license and, if you live in the United kingdom long enough, even for British citizenship.
The General question of people trying to migrate under this program is: Am I a highly skilled person ? Home Office UK has a special department located in Sheffield which reviews all cases under HSMP. The program has a points based system, and depending on your Age, Education, Past earnings and English language skills you can be found qualified.
The interesting thing is that before November 2006, knowledge of English language was not a requirement at all.
In a few words: to be qualified you need to pass 75 points mark:
Bachelors degree - this gives you 30 points.
Age - being younger than 27 years gives you 20 points.
Past Earnings - for Countries like Russia, take 25 points if you have earned 8100£+ before taxes for the 12 out of last 15 months .
English Language is a mandatory and must be IELTS Overall Band 6.
The most difficult part is to convince Home Office that you possess what you claimed. List of evidences, that can be supplied to prove facts in your application, is predefined and sometimes is quite hard to collect.
Full information about HSMP can be found in the Guidance:
http://www.ind.homeoffice.gov.uk/6353/11406/49552/hsmp1guidanceapril07.pdf
Note that Immigration agencies, being horribly expensive can not help you to gain more points, they can only help you to prepare documents.