|Scary Microsoft employee makes your life hard|
This post just builds on the post found here and gives you some shortcuts to solving the issue.
Before visting that link run phpinfo() to check the compiler that was used for your version of PHP.
Next thing to remember is that nts is short for "not thread safe" and ts is short for "thread safe". The 53 or 54 in the file names of the dll's you download from (Microsoft correspond to the version of PHP you're using (5.3 or 5.4).
Finally if you get the error about "This extension requires the Microsoft SQL Server 2012 Native Client ODBC Driver to communicate with SQL Server" you can download the native client from Microsoft. There is an .msi installer for just the client down the page if you don't want to download the whole package.Tip