The smallest wire at Rat Shack is 30awg magnet wire, which is technically the same size as what I used for some of this, but it's actually thinner as the insulation on it is an enamel, so it's a lot thinner than the coating on 30awg Kynar wire.
You should use whatever awg ya need for whatever you're doing. The 28awg is a little big for soldering on those IC pads, but could be soldered to a Via with little issue, so it all depends on what/where/how you're doing it as to what awg will work better. They have the 30awg Kynar (Wrapping wire) at Rat Shack also.