This may not be the sagest advice, however it did come from my IS Department: with regards to my users, instead of using a digital certificate (to authenticate a code source - my personal choice), we set their security levels to LOW to bypass macro enabling warnings.
Yes, macros (also known as VBA-Visual Basic for Applications code) can harm your computer, BUT (and here's the big BUT), they can also be an integral part of your daily interaction with Excel and other office programs, so don't discount them!
