The gear I am using for mobile podcasts is via recommendations from Craig Patchett @ Godcast’s:

• iRiver iFP-799 (mp3 player), and
• Sony ECM-MS907 (microphone).

I am still learning how to tweak the setup but I am very impressed. I may even use this setup for my full podcasts (Tech Rag Tear Outs and Tech Tidbits Daily) versions also since the quality is pretty good.