from Poison:

DrkIIRaziel posted a patch for the WPA bug at May 20, 2008 in Hostcore google project. I just saw that this night with sunjon's reminder, OK, it's all my bad...
and yea, I got no psp in hand so it has not been tested, I would be glad if somebody can tell if the binary work.

Changelog:
- fix bug#0011(Can't connect to nethost with WPA protected network setting)

-=REQUIREMENTS=-
A PSP (either fat or slim one) with 3.80+ m33 custom firmware.
Start usbhostfs_pc or nethostfs_pc at your PC side. if you use nethostfs, make sure your computer connect to a wifi router or you are sharing your network on a wifi card.

-=INSTALLATION=-
Copy HostCore folder to your memory stick root.
Add a line ms0:/HostCore/hostcore.prx in your vsh.txt (ms0:/seplugins/vsh.txt), don't forget to enable it.
Open ms0:/HostCore/conf.txt and change some values if you need.

-=HOW TO USE=-
Run usbhostfs_pc or nethostfs_pc on your PC, host a folder which has same structure as ms0:(it contains MUSIC, VIDEO, ISO etc..).
for example, type the following command on your console
usbhostfs_pc /Volumes/Home/PSP/
in wifi case
nethostfs_pc -c 4 -d 20 /Volumes/Home/PSP/
(If you don't pass a folder path to it, it would use the current work path. when you are using windows, you can just place usbhostfs_pc or nethostfs_pc in a folder which contains MUSIC, VIDEO, ISO etc. and double click on the usbhostfs_pc or nethostfs_pc binary to host.)
Go to PSP XMB, press the hotkey(default Note key) to switch on the mode you need.

-=SOURCE=-
http://code.google.com/p/hostcore-psp/source/checkout

-=NOTICE=-
If you find some bugs, feel free to report it to me. you can either leave a message at my blog or send me an email.
In wifi case, only infrastructure mode connection support.

-=CREDIT=-
Thanks to Matchung, drkIIRaziel, Gilleco, Cooleyes, Real.KK, SilverSpring for advise and testing.
Thanks to everyone who has contributed to nethostfs, usbhostfs.
Thanks to everyone who has contributed to the PSPSDK.
Thanks to everyone who has contributed to PSP CFW.