Suggestions needed

Hi,

Gurus,please provide your guidance.

I have an IDOC ,which used to send requet to a webservice through XI.The webservice picks up the data process it and send it back to SAP R/3 system.

To build this IDOC-XI-Webservice scenario,what are the details,I should gather before starting this scenario?

Example:Need the WSDL description,the webservice location,which Process/function is taking input values and providing back some output.

Any step-by-step example for this scenario available?

What are the tools involved to test Webservices?

Any other details/tips you would like to share about this scenario?

Regards,

Mohan.