It's not the 40% that was bandied about late last year, but it's something; digital copies of Vita games will be reduced by about 10% compared to their physical counterparts. A collection of Vita games, including Modnation Racers and Uncharted: Golden Abyss, have been published onto the North American PlayStation Store and are usually reduced by about $3 to $5.
That's not a huge amount, considering what you're giving up by going digital (a fancy box, an actual item that in theory can never disappear), but it'll be enough for some people to choose the download option over the "going outside" option. Uncharted is $45, compared to it's $50 physical price; Modnation is $27, while it's physical counterpart is $30.
Whether the publish was a mistake and whether these are the final prices are yet to be seen, although with less than a fortnight until the launch of the Vita, I don't think we'll be waiting too long.