what is the course duration of flash, good institude for it and what are the career aspects?

Answer 1

The couse duration is anywhere form a day to two weeks. Do you just want to learn the basics, or do you want to do advanced scripting? You can also find a bunch of free tutorials on the web.
I can't really recommend a good institute without knowing your location. Adobe lists various things that they endorse: http://www.adobe.com/training/
As for career aspects, Flash is just one cog in the big picture of creating a site. You'll improve your chances (and pay) if you have other skills, too.
Here's what you can expect in the UK: http://www.itjobswatch.co.uk/jobs/uk/flash.do