Jamie Thomson demonstrates how to use .NET scripts in a SQL Server Integration Services (SSIS) pipeline to add Regular Expression support. By simply dropping in a Script Component, you full access to the .NET framework. From there, it is easy to add a regular expression in code.
If you find yourself writing a lot of regular expressions for row filtering, you may want to try the Regular Expression Transformation provided by the people at SQLIS.com. This component redirects rows that do not pass all of the regular expression tests specified.