This is a maximally confusing question, since of course HTML documents are
ASCII documents.
If you mean "how can I translate whatever format cues exist in the originals
to HTML tags?" then one suggestion -- if you're a Windows type -- is to import
your documents into Word for Windows 6.0x and convert them using Microsoft
Internet Assistant. IA is free, from
ftp.microsoft.com/deskapps/word/winword-public/ia.
It'll do its best to translate formatting, including some tables & forms. Just
don't try installing radio button!
There are similar translators for Word Perfect et al.
Hope that's a help,
Stu Harris