A PSP (Playstation Portable) kernel exploit found by Total_Noob is to be released sometime between December 20-24 on PSPGEN.com. It is for firmware 6.20.
This exploit is to be loaded through the HBL (Half-Byte Loader). The HBL can be loaded through the (free) Patapon 2 demo.
A HEN (Homebrew ENabler) has been coded to this exploit which will allow homebrew to be launched from the XMB (PSP menu).
Updates are on Total_Noob's blog.