Also, one do it the other way around: use SQL queries to read (and update!) Excel files. For examples, see http://support.microsoft.com/kb/306397 and http://sqlserverpedia.com/wiki/Access_Excel_Sheets_as_a_Tabl...
Can you use it with arbitrary sql (non MS) servers on other hosts?
Yes, the latter is an ODBC option, which gives you arbitrary connectivity.
I think an even easier way is to use .NET/Mono with the open source library called EPPlus which lets you read and write Excel 2007 (Office Open XML/xlsx) files.
I can go to the Data tab, click on the ribbon item "From other sources:From SQL server" or "From other sources:From Microsoft Query" in far less time than it takes me to read this blog post.
Am I missing something? (other the possibility for SQL injection attacks by users of that spreadsheet)