Sergio,

>Does anybody know how to search for words within a tiff file?
>Is it posible?

You may want to look at Microsoft Office Document Imaging (MODI) with MS Office 2003. It gives you a COM interface to their document image viewer, which includes OCR and Find capabilities.

Here is the documentation:
http://www.microsoft.com/downloads/details.aspx?FamilyId=8F93E445-B1CF-4477-A373-E17417D616BC&displaylang=en