Sony is expected to release PSP Go later this year, a smaller and lighter PlayStation Portable (PSP) handheld game machine, according to video game websites.

The information "leaked" when the device appeared in a video distributed through Sony's online game information distribution service for paying U.S. subscribers.

PSP Go is significantly lighter than the current model and comes with a 3.8-inch display, which is smaller than the currently available model. PSP Go has also a key pad that slides out from below the screen, according ot the clip. It is expected to have 16MB o fmemory on board and BlueTooth connectivity. Sony seems to drop the failed UMD disk format.

The announcement on the new PSP is expected to be officially made at the E3 video game trade show that starts on Tuesday in Los Angeles.

New version of WiFit

At the E3 game show, Nintendo is also expected to launch a new version of the Wii Fit home exercise game. The new "Wii Fit plus," is expectd to allow users to compete with friends and family over the Internet.

Nintendo will also launch a new version of its popular "Mario" game series in the second half of 2009, the Nikkei said.

Nintendo's E3 press conference wil be held on Tuesday, June 2.