you can do this as a macro, something like this in your .vimrc (i'll let you fill in the rest of the entities ;-) ):
let @a=':%s/á/\á/g^M:%s/é/\é/g^M:%s/í/\í/g^M ... '
note that ^M is a special character entered using Ctrl+V, Ctrl+M.
scomar
2010-06-16 16:13:18