short answer. ODBC drivers ? are available.
try
http://www.ivsol.com/vpcgi.htm
Longer answer, ODBC is an API (programming Interface) and as such the ODBC libraries are available for Linux, but it's not quite as simple as setting up an ODBC driver in windows. You can write applications that use the Linux ODBC to access an external database.
Your best options (in no order).
Your requirements sound like you would need to be running the database access from the server side, therefore you will need to do something like a cgi form, now, how this is implemented is the real issue.
Perl is an option, write the cgi scripts in perl and you should be able to get to your SQL database using perl DBI interface routines.
You could also use JDBCto get the connection to the SQL server from your web server (see http://java.sun.com/products/jdbc/download.html for download details, and search on the sun site for other info)
The most obvious (but least acceptable !) option would be to use Fusion to create your database access web pages/forms, set up the ODBC connection etc, and then run with a seperate web server on, say, an NT/2000 box (I assume you will have your SQL server running on NT/2000 anyway, you didn't actually say if you are using MS SQL?) and link your web pages to that. It's a tad messy, not intergrated, and could cause other interesting problems (such as do you want your SQL server to be seen directly from outside?), but has the advantage of getting your system up quickly whilst you could work on a more intergrated (i.e. Linux server based) solution
