Gary13579 (Why does that name sound familer? Oh yeah!) has released a program called PSP News Reader. This program will download RSS feeds to your PSP, so you can read them on the go. It will not display/parse the XML file, so currently you need to use a program like FileAssistant++ to read it.

Current features are:

• DHCP supported
• Different files for each XML feed
• Up to 5mb feed (for some reason it doesn't work over that.... I will try using a ported libcurl to get this working, for MP3s)
• WiFi profile selector (a bit buggy...)

I plan on adding XML parsing, MP3 playback (Yes, RSS MP3s on your 1.5 PSP ), and be able to use the GUI without having WiFi enabled (saves battery).

Download PSP News Reader v0.1b from PSP 3D here.
You can read more about my projects at http://psp.indocron.org/.