Want to pull data from one excel spread worksheet to another

I want to pull data from one Excel worksheet and put into a different workbook.

The challenge is the name of the file is dynamic, it changes from one month to the next (Expenses_Aug 09, Expenses_Sep 09, etc). This name is in a cell.

So i would have Sheet1 in Expenses_Aug 09, Sheet1 in Expenses_Sep 09, etc. I want to copy and paste all of Sheet1 into a static sheet in another workbook.

How to best do this?