Hello shirish,
Beta runs are scheduled to run quickly using downloaded beta programs, which may have to be given security clearance manually if the firewall objects to them. These runs are special and sometimes the grid operators intervene to give special credit. They are supposed to reveal problems that did not occur on the alpha computers. Sometimes some computers seem to choke on code that others are happy with.

Lawrence

It often takes people a while to work this out, but it's not BOINC doing the work it's the science applications that the BOINC client downloads that do the work. The BOINC client is just the framework, that is the systems at both the client and server end, for handling work distribution, credit allocation, unit validation benchmarking etc. BOINC actually stands for: Berkley Open Infrastructure for Network Computing. WCG is one of many projects to use this framework.
Berkley also, from time to time, release beta versions of the BOINC client for testing and they have their own discussion forums for that, but that's not what we do here. Here we're about testing new science applications and variations on existing ones particular to WCG.

and welcome ;)

There are no beta's running at this time. You need to keep an eye on the beta forums, they will announce it there.
Yes, you get credit.

If you go to My Grid you're half way there... then look to the left.