Before you paste, select all cells of the Excel worksheet (click at top left corner, "cell" 0,0,), then Format> Cells>Alignment tab> Merge cells. You now have a "celless", actually a "one-cell" worksheet. Now paste as usual. You may be able to set page breaks and margins at Page setup and review and adjust at View>Page break view. (I have not done this before, and hope that it works for you, or gives you an idea.)
I have tried copying and using "paste special-text" a total of 10 PT slides(one file) into an xls spreadsheet. Unfortunately, several lines in pt come out as one cell in excel and I need to make each line its own separate cell. Also, whenever there is a carriage return in a pt slide it appears to translate as starting a new cell. I can use a time consuming method of going into the excel spreadsheet, adding blank rows and retyping the lines of text/data, but that will take a very long time(the xls spreadsheet already has 1250 rows and 10 wide columns. Any advice or a handy macro? I am using Powerpoint and Excel 2000 and have a Dell Dimension 2350 with XP SP2.