Blackberry what SDK and language are used

I am new in Blackberry. Can anyone help me out for following queries?

1. Which SDK is used in Blackberry?
2. In what language are Blackberry applications developed?
3. Can we call webservices through Blackberry applications?

Blackberry applications are written in Java. They support Java ME as well as some additional blackberry specific APIs. Check out http://na.blackberry.com/eng/developers/javaappdev/overview.jsp

As for calling a web service, yes you can do that as well. Check out the Rapid Application development tutorial at: http://na.blackberry.com/eng/developers/rapidappdev/