application-list of variables in PLC Compactlogix

I have to write an application (VBA or web application) that allows user to save a list of all variables in a CompactLogix PLC and their values, and write it in Excel. Someone can tell me where I can do start?

Go to www.opcfoundation.org, they have a list of companies that offer what you need, they´re not free but your can try some of them free for a while.

The one I use is called XcelReporter and is produced by www.sytech.com

they asked me to write it... I can import data in excel, but only if I saved them on a dataview, and importing 800 variables in a data view is not a solution... is there a way to connect to the PLC and obtain a list of all variables (even if they aren't in any dataview)? a socket connection can be a solution? (I can use 1768 eweb)