I had a look at Keroplayer and it's fantastic. I was looking for a great standalone podcast aggregator/player, and because I've got dmBlogger already installed, I didn't have to install the extra Ruby files (or mplayer for that matter).
Only problem is: it's in Japanese. So I translated it into serviceable English.
Hope this helps.
HOW TO INSTALL
Replace the "keroplayer.rb" file on your Z -- in /QtPalmtop/bin/ depending on which media (SD, Internal Flash) you installed it -- with this one.
Keep in mind that this is only a rough translation working backwards from the Ruby commands and a lot of trial and error. I know no Japanese.
[EDIT: I've been doing more work on the translated GUI and it's shaping up nicely, so I started a
new Keroplayer thread in the more general Software forums and have posted the English GUI file (with instructions and replacement icons) there. Thanks.]