Halves.
The assignment of "U1A" and "U1B" to a particular half of a dual op amp is at the discretion of the person drawing the schematic diagram. I usually use the lower-numbered input pins for the "A" section and the higher numbered input pins for the "B" section myself, but that's me. Harvey Lithehquiate may do it just the opposite and that's OK.
To identify the pins of the op amps, you need to get a data book. I suggest the linear data books from National Semiconductor. They can be purchased through Digi-Key or if you get on the right mailing lists, they can be had for free directly from National. Or you can use one of the many on-line IC sources for diagrams and specifications.
Dean