Don't know what exactly you are trying to do. Below links would help you understanding, I believe:
For exporting into Excel, <apex:page standardCOntroller="objectName" contentType="application/vnd.ms-excel#YourFileName.xls" > - How to export data in Excel or PDF format using Visualforce (https://help.salesforce.com/apex/HTViewSolution?id=000003176)
For passing parameters, there are already various articles if you Google. http://www.forcetree.com/2009/06/passing-parameters-to-visualforce-page.html http://blog.jeffdouglas.com/2010/03/04/passing-parameters-with-a-commandbutton/ https://developer.salesforce.com/forums?id=906F000000099LuIAI
For exporting into Excel, <apex:page standardCOntroller="objectName" contentType="application/vnd.ms-excel#YourFileName.xls" > - How to export data in Excel or PDF format using Visualforce (https://help.salesforce.com/apex/HTViewSolution?id=000003176)
For passing parameters, there are already various articles if you Google.
http://www.forcetree.com/2009/06/passing-parameters-to-visualforce-page.html
http://blog.jeffdouglas.com/2010/03/04/passing-parameters-with-a-commandbutton/
https://developer.salesforce.com/forums?id=906F000000099LuIAI
Trust this helps.
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Abhi