OGR Source and Parameter Query

[Tim Pascoe]

I'm relatively new to MapServer, but I have so far developed a nice simple
application for displaying data from a database of national sampling
locations. The base information is coming from several WMS servers, while
the sample point information is an OGR data source from my local MS-SQL
Server instance.

What I'd like to be able to do is pass a parameter to the query being used
as the OGR data source, allowing a user to select a particular study from
the database, and thus display the sampling locations for only that study.
Does that make sense?

I looked through the archives, and didn't find anything that seemed
immediatly usefull, so I thought I'd see if anyone else had done something
like this. I'm running PHP 4.3.8, Mapserver 4.2 (precompiled Win32
binary), and IIS 6.0.

Any help is much appreciated.