What environment ( Processor / OS) are you targeting? Each platform has its own tools.
For Intel / AMD PC processors running Windows then Visual Studio works very well, but is a bit of a heavyweight if your just doing some simple assembler routines for a class, or an embedded controller.
You might want to start with something like http://www.wrox.com/WileyCDA/WroxTit...76459561X.html
Co Author "Professional SQL Server 2005 Administration"