The default mode of operation is that exported photos are not shown in the Lightroom Library Module.
If you really want your exports to show in the Library Module (which most people don't do), then you could check the box in the Export dialog box that adds the export to the catalog.
It's not clear to me why you want this, as in most cases I don't see a good reason to include exports in the Library Module.
Thanks for the info. I am fairly new to LR. I was exporting to outside of LR before I would put them in a website or have them printed. I have 3 drives. I would not be consistent where I put them and would waste time searching. I am trying to use LR for every thing and now I can tag them or file them and be able to find them at a later time. I do have many exports but I think it will be easier this way.
Consider using publish services for exporting photos bound for websites - there is a feature: "Show Published Photo" which will take you to the exported photo.
Regular exporting may (or may not) still be more appropriate for printing.. - consider adding a keyword upon export for print. Even if you don't add exports back to catalog, you can use your OS or an external photo app (like ACDSee) for locating those files, if you forget where they are..
Thanks all for the help. Will surely use a special keyword for exporting.