Thanks to Patrick, Mark, and Mart for noticing that Packt (our publisher) has provided Chapter 5: Searching MCMS with SharePoint (link removed as no longer active) from our new book, Advanced Content Management Server Development, as a free PDF download for your benefit.
In this chapter we discuss how you can configure SharePoint Portal Server to act as as search engine for a MCMS 2002 site, as well as how so execute queries against that search via the OOTB SharePoint web services. In addition, we detail some tweaks you should do to your MCMS site to make the indexing more performant.
As Patrick Tisseghem noticed, these techniques can be used for non-MCMS sites (like vanilla ASP.NET sites) as well.