Two separate reports have surfaced claiming that Sony's upcoming handheld (codenamed NGP) will be named PlayStation Vita (or PS Vita).
The image found in the screens tab is taken from a blog that has been made private shortly after it was published (cached versions available here and here). The image is said to be a prepared graphic for the E3.
Several websites have also reported anonymous sources confirming the name. Our own sources at a development studio confirmed that they have heard the name "Vita" more than once before it made it to the internet.
Perhaps the strongest clue is the fact that Sony Computer Entertainment developer network website has added the word Vita to its list of subdomains which include PS3, PSP and NGP. Right now vita.scedev.net leads to the development network website unlike nonexistent product names such as ps4.scedev.net which lead to nowhere.