Jose,
Well, I would say that You could use a softaware such as stattransfer which would solve this problem. If you dotnt have it, I would recomend any other statistical software is usually able to do so. I usually work with stata or R.
With stata you may save he spreadsheet as csv or tb separeted and import within stata and save in stata format.
With R is even more simple because thereis some packages that are able to import directly from xls and then save it in stata format or dbf format.
Usually stata format is the most friendly for epidata entry. If you dont have any experience with R, perhaps you will find easier to use a grphical interface such as Rcmdr or pmg. To install the Rcmdr and use R with a graphical interface, after installing it type "install.packeges("Rcmdr")" and afer the install type "library("Rcmdr")" The rest should be more intuitive!
Abraço forte e que a força esteja com você, Pedro Emmanuel