For those who use Sonar and don't want to buy their MP3 encoder, there are instructions online explaining how to set up LAME to work automatically as one of the SAVE AS MP3 options in Sonar.

And since LAME has switches that let you save MP3s in a variety of ways, you can even set up different menu options for multiple switch settings

http://forum.cakewalk.com/TUTORIAL-Getting-LAME-MP3-Encoder-to-Work-With-SONAR-m1255631.aspx