Bloglines Mobile
There are a few PDA aggregators out there. For example:
But there is another way of providing feeds for mobile devices: just format your online feed service to be mobile device friendly.
Bloglines offers just such a service:
View it here: http://bloglines.com/mobile
A major drawback of this approach is that these feeds are only available if and when you have wi-fi at your disposal, but it also doesn't require that you download yet another piece of software. -worth a look anyway.