START, NEW OFFICE DOCUMENT, SPREADSHEET SOLUTIONS - If you dont like that
one then go to http://office.microsoft.com and check out the templates they
have on there.
Go to Microsoftoffice.com then go to templates and from there you can find a variety of invoices. Once you find the one you want, click download and it will automatically download it into MS Word or MS Excel. You can save it as is or modify it before saving it as a template.