We had been using Levelator, an excellent software to adjust the audio levle for podcasting and there is a good news for podcasters as it supports 24 bit files also. Just drag and drop your .WAV or .AIFF file and you would get a good quality audio file ready for podcasting.
Other improvements :
- Reduction in certain unnatural volume adjustments.
- Soundtrack Pro 2 .aiff files are now supported.
- Adobe Soundbooth files are now supported.
- Unicode filenames are now supported.
- More here
Thanks to Download Squad for pointing to this as we almost forgot about using it.