Gadget Madness reports the existance of the first unofficial PSP 1.5 web browser to hit the net:

You could wait, and wait, and wait for Sony to release V2 firmware for the PSP so you could browse the web. You could also royally screw up your PSP by trying to load Japanese V2 firmware. OR, you could simply follow the link below to grab the 1.5 (works on 1.5 only) web browser for PSP which will work on your US system, if you don’t mind pressing the select button to switch the language from Chinese to English. (FYI, try this only if you are confident with what you are doing. We’re not condoning this unofficial software, just reporting it.)

Here’s that link, and I’d also like to say that we here at Gadgetizer do not support or recommend this software. We’re just echoing the link as well.

Underground Web-Browser released for the PSP v1.5.