Microsoft Security Advisory (954462) - Rise in SQL Injection Attacks Exploiting Unverified User Data Input

A timely advisory from Microsoft on SQL Injection attacks plus some tools to help secure your setup are available on KB954462 with more information here and ISC's commentary here.

Of particular interest is the free Scrawlr tool available from HP. That could be a useful way to see if your server is vulnerable before the bad guys find it,