Share 'File formats for Podcasts'

I may need a wee hand with this from someone if I may? I have been doing video podcasts and loading to podomatic in .mp4 file format. I do most of the screen capture recording in Camtasia Studio at the moment which I find relatively easy to use. However - the .mp4 format is for playing on one's iPod obviously. I have tried producing the same recording in other file formats compatible for podoma…