[EDIT] PlayStation LifeStyle has pics of the retail box here.
Some pictures of what appear to be PSP Go! from the June issue of Qore surfaced today.
Claims stemming from the supposed leak say the system has 16 Gb memory, a slot for more memory, it will not replace the PSP 3000, and it is to be released in the fall with no price point attached at this time.
The images look real, but you can never be too sure.
Judge for yourself until E3.