The Presidents Hundred Tab, although popular, is unfamiliar to most Airmen.
Although there is no picture of the President's Hundred Tab being worn on an Airman's uniform, images of Ranger Tabs being worn suggests it is in regulations. Documentation from Airman earning the tab also suggests this tab is within regulations for wear on both the blues and ABUs.
More information on the President's Hundred competition and tab will be listed on the President's Hundred page. It will be updated with all of the information required to compete and uniform guidance.
Update 11/28/14: I have contacted a recipient of this award and found a picture of it being worn on ABUs. Click Here