We have a client that has a WSS3 install with a single site, but wants to start creating sites for each functional group inside their organization. The bummer was WSS3's search was limited to a single site. Well, we could just replace it with Search Server 2008 Express, but that runs over SQL Server 2005 Express and is limited to 4GB on the databases so it would be a hassle to manage when it gets big.

The answer is to use both.

Here's the steps to make a test environment for this from scratch:

1. Make a virt using Windows 2003 R2 w/ SP2
2. Add web server role
   
3. Windows Update
4. Install WSS3 w/ SP2 which gets me the Window Internal Database (not limited to 4GB) for SharePoint content.
5. Let the Configuration Wizard do its magic.
6. Install Search Server 2008 Express
7. Let the Configuration Wizard do its magic again but don't let it replace your WSS3 site - tell it to make a new search site on a random port.
8. Turn on the "Office SharePoint Server Search Web Parts" site collection feature on the WSS3 site
9. Install SharePoint Designer 2007
10. Open the Search Server site's /results.aspx page
11. Save as to WSS3 site as /results.aspx (with Don't save for the images/css junk)
12. Add a Search Box webpart to the /default.aspx page of your wss3 site setting the "Target search results page URL" to /result.aspx
    

To test, I created a subsite and uploaded a sample document to a doc lib there (/inetpub/wwwroot/iisstart.htm) - let a crawl happen then searched from the root site for the word "Construction".

Now to tune this a little better, you might want to set the memory limits on the two instances of SQL running on this box now (MICROSOFT##SSEE and OFFICESERVERS). My understanding is that SQL server is super memory greedy, but the express and WID versions are less so but they still will probably push at each others memory causing them to drop cache buffers and page out IIS, ASP.NET and SP core stuff, so better to limit them.

I did this by creating the following text file (sqlconfig.txt):

EXEC sys.sp_configure N'show advanced options', N'1'  RECONFIGURE WITH OVERRIDE
GO
EXEC sys.sp_configure N'max server memory (MB)', N'256' -- <== mod this value to around 1/4 of installed memory - 1024 max
GO
RECONFIGURE WITH OVERRIDE
GO
EXEC sys.sp_configure N'show advanced options', N'0'  RECONFIGURE WITH OVERRIDE
GO

Then I ran this from the command line:

sqlcmd -S localhost\MICROSOFT##SSEE -E -i sqlconfig.txt
sqlcmd -S localhost\OFFICESERVERS -E -i sqlconfig.txt