I agree with Warren -- you should be able to go to design center, but for a customer reference point.... here are some answers.
1. How to get Task waiting for inputs of a user by web service.
[SHAUN]: There is a web service for Task @ http://<CPO HOST>:<Web Service Port>/WS/TASK?WSDL which has Create/Update/View methods. I have not used it before so I'm not sure the exacts. Look to the NorthBound Web Service guide for help. It's on cisco.com in the documentation area for CPO.
2. How to get instance id of a process .
[SHAUN]: There is an exposed property if you are looking in the process itself. When you start a process via Web Services, you get the ID as an output. What are you trying to accomplish? Again look to the NBWS guide.
3. What is process start point ID or Name.( which is one of the parameter to start a process by web service ).
If you configured a start point in your process, then you can send that in a web call, otherwise remove it as it would be optional.
4. What is get-output variables by web service.
[SHAUN]: If you use the processinstance wsdl (or http://<CPO HOSTNAME>:<WS PORT>/WS/ProcessInstance?WSDL there is a "GetOutputVariablesFor<PROCESS_NAME>" that you can use to get the output of variables once the process is complete.
CIAC Adoption Pilot Engineering Lead