White peach is a generic term that refers to a number of peaches with whitish flesh rather than yellow.  They tend to ripen to a crimson skin and the flesh can start to blush this color as well.  White peaches have their claim to fame in their amazing sweet flavor.  They have a very low acid level which eliminates most of the tang that is typical of yellow peaches.  You won't believe how much sweeter they taste, even though the sugar level is about the same.