If you want to display  more search  results, you need to modify the
Search Results.DWP file. To do this, browse to this address...
portalname/Search.aspx?mode=edit&pageview=shared

On that page, you'll see Modify Shared Page on the right. Click
that > Modify Shared Web Parts > Search Results. On the Search
Results web part heading, click the arrow on the right hand corner
next to the X, and choose "Export." Save the file,
then open that file up in Notepad or some other text editor. There
will be a tag named <MaxMatchingItemsNumber>...just edit the number
in the tag to display the number  of results  you want. I don't know
if there's a limit or not, but this will let you adjust the number
of results you see.

I only have http://sharepointTeamSite/sp/default.aspx (where the search  box
is located at the top right corner of the page). I can't see the "Search
Results" web part to modify.

Copy the URL into your browser and replace portalname with your portalname.

When you do a search, what you are seeing is a grouping. By default, it's set to
5. Within each grouping, if there are more documents, you will see a link 'See #
more results  ...'.

If you want to display  more than 5 groupings, then you need to edit the tag
named <RowNumberForEachItem>. By default, it's set to 5.

The tag named <MaxMatchingItemsNumber> will display the total number  of results
on each page. By default, it's set to 40.

We have WSS, not SPS. I searched for search.aspx on the server where
Sharepoint is installed and didn't find it.

I'm new to Sharepoint and I can't figure out this seemingly simple task.

Was just going to ask if you were running WSS instead...I honestly
don't think there's a way to modify the number  of search  results in
WSS, which uses SQL Full-Text Search (as opposed to SPS, which uses
MSSearch). Has anyone else tried this? Here's an FAQ link that
explains WSS search results  more thoroughly...
wss.collutions.com/Lists/FAQ/DispForm.aspx?ID=115

I don't know if there is a way to modify it for WSS.