Right now you can't. For regular downloads you might have to wait for hackers, but for the podcasts(especially if you can get them through iTunes), there may be some hope that Apple will do something about that.
One interesting thing though, you can stream certain files on Safari. I was able to use my Newsguy Usenet web access to stream mp3 files via WiFi. You can see it buffers the file while playing it, so it IS downloading it to the Touch. And I am talking 100MB files(radio show). I'm sure some motivated hacker will figure it out sooner or later.
i believe its just another software update which will resolve all the problems with the current iPod touch, (i.e. no input for iCal..etc)
Its just a matter of time.