You could do that two ways at least - create a new series whose value force
them above the error bars and then attach data labels for them or you could
use the XLChartLabeler program which is free on the internet.  Also John
Walkenback has an add-in to do this for you.  These add-ins allow you to
connect the data labels to any range in the spreadsheet and to move the data
labels any distance from the data points.