Youlean has released Freq-Balancer, a simple tool that will help you with mastering by balancing the frequency response of your songs.
Freq-Balancer analyzes the frequency content of an audio signal and automatically applies an equalizer that evens out the frequency balance towards a curve found on many commercial tracks. When Freq-Balancer analyses audio, it measures the audio's frequency content over a period of time. It splits the incoming audio signal into 7 frequency bands. Then it measures and compares the audio levels within each band. Finally it applies EQ to compensate for any uneven frequency balance.
Freq-Balancer is available as donationware for Windows as a VST effect plug-in.