you can find the best tutorials in the help provided in the 
s/w itself

Analysts and developer are imperfect.We cant ship
(successfully) a project that's not working properly.Its 
done to find the bugs,find them as soon as possible and get 
them fixed.A good tester is not the one who find the more 
bugs but he is the one who get them fixed.Good software 
testing is a challenging intellectual process.
Go for it!

if a company developes a software and and want to release 
in market.but before it release in market it should check 
how perfect the spftware it is. so they give their beta 
versions to the testing department.so the testers tests the 
that beta version and fined the bugs and informs the 
company people.so they canrectify the software.after 
rectifying, the software is again given to the testing.and 
final report of the testing shuold be perfect. then the 
software is released into market
so testing necesarry. ad this is software testing

yes,win runner support .NET technology

No way...Win Runner do not support .net technology, it 
supports xml, html,VB or some other lang, We can use QTP 
for .Net applications.

as per my knowledge winrunner do suppot technologies such as
.net,Java