According to Japanese magazine Dengeki PlayStation, at least two of the PlayStation Vita launch titles will have their digital-download versions retail for less than their boxed ones.
The magazine has confirmed that the boxed version of Uncharted: Golden Abyss has an official price of ¥5,980 ($78), while its digital download version will cost only ¥4,900 ($64). Hot Shots Golf 6 will also show the same price discrepancy as is has an official retail price of ¥4,980 for the boxed version, and ¥3,980 for the digital-download.
We don't have pricing info about any other Vita titles yet, so it is probable that this will be a common trend for all Vita games. It is worth noting however that most retailers offer discounts and sell games for less than the official retail price; unfortunately, this isn't usually the case with digital-downloads (not before they hit the bargain bin).
In the same issue of the Japanese magazine, Sony's head of development, Yoshio Matsumoto, hinted that PSP owners will be able to buy digital-download versions of the games they own on UMD at a "special price."