Importing text files into Excel

When importing a tab-delimited text file, some of the
fields are things like zip codes, which I want Excel
to treat as character strings even though they are all
numeric. The Import Text Wizard can change the
type of the field from "General" to "Text". But the
import file is quite wide, with lots of similar fields
and I don't want users to have to manually reset the
field types every time.
Is there a way, without a macro, to imbed something
in the import file to force Excel to treat the field
as "text"? (When entering data interactively
into Excel, the single quote (" ' ") tells Excel the
field is "text". Anything similar on import?)
Thnx.