The various alternatives for podcasting are thoroughly compared at:
http://www.podcatchermatrix.org/
Take your pic and start using them.

I have been using www.audacity.com , a free recording software

To have a complete view of tips and suggestions on podcasting visit http://portablepd.edublogs.org/category/3-audacity/

and also some fellow wikis such as http://wellesleytechnology.wikispaces.com/Podcasting

Try this good and free software to record your voice in MP3 form and them keep it in a file that you can upload in any website, blog or wiki of yours. As you record your voice it is automatically stored in your PC!:
http://www.freedownloadscenter.com/Multimedia_and_Graphics/Misc__Sound_Tools/Audio_Recorder_for_FREE_2009