Microsoft SQL Server family includes free Express edition, that is fully functional, however has some limitations which prevent from using it in development process. SQL Server Profiler is not available in SQL Server Express edition.
There are a few free open source software that acts as Sql server profil. One of them is AnjLab.SqlProfiler available to download at http://sqlprofiler.googlepages.com/.
AnjLab.SqlProfiler
This free performance tool for SQL Server Express – http://sqlprofiler.googlepages.com/.
It is an open source project by AnjLab.
It provides the most of functionality standard profiler does, such as choosing events to profile, setting filters, etc. Also it has a GUI.
By now there are no analogue free tools as AnjLab says.
SQL Server 2008 Profiler
SQL Server Profiler is only available with following Editions of SQL Server 2008.
1. Enterprise Edition.
2. Standard Edition
3. Work Group Edition
4. Developer Edition
5. Web Edition
SQL Server Profiler is installed when you install SQL Server Client tools.
Source: http://msdn.microsoft.com/en-us/library/cc645993.aspx