Yes, you can and it's easily done!
- Download the Say I do excel template.
- In a Google Docs spreadsheet click "File" and then select "Open"
- A pop-up will open, from there select "Upload"
- Find the Say I do template you just downloaded
- Fill out the spreadsheet
- When finished click on "File" and select "Download as"
- Download the file as "Microsoft Excel (.xlsx format)"