Look at the ranking in last Monday's Financial Times for masters in management programmes. Many of those UK schools, like Cass, also have MSc programmes in business computing areas with very high employment rates and good salaries. Look for them. An MBA from a low quality school like Bedfordshire is worth much less than an MSc from an internationally accredited and ranked schools.

Thanks for your quick reply. In fact, Im looking for a master degree focus on IT or information systems. But I dont know which university has good reputation about IT. Can you give me some help? Thank you so much.

That is exactly what I am suggesting. The programmes in IT at those top business schools will not only have a good technical element but also a strong business element, careers services and higher salaries. Cass, Imperial, Manchester, Warwick, Cranfield and so on are all worth looking at.

I'd generally agree with Duncan. In general, you want to do a program from a school with accreditation from one of the three international organizations (AACSB, AMBA, EQUIS.) That puts most of the respectable MBA programs (Cambridge, Warwick, Oxford, etc.) out of your reach financially.
<blockquote> And have any chance working after graduation in IT field for a non-EU citizen like me?
</blockquote>
UK visa regulations have shifted recently, so it's increasingly hard for international students to find work after graduation. You basically have to have a job lined up by graduation in order to stay and work. If you do the MSc at Cass, be sure to take advantage of the career services workshops, career fairs, and company presentations.

Do MiM in above mentioned colleges require GMAT
if yes then in what range?

Those that do will be looking for over 550, sometimes more. Visit their websites.

I strongly agree with you, should take a master degree at good university than at non accredition MBA programme, even at US school.