There is no standard definition of "Information economics". If you are interested in the economics of the IT industry then apart from Varian's "Information Rules" mentioned in another comment, there is

* Oz Shy, The Economics of Network Industries.

If you are interested in research at the interface of economics and theoretical computer science you have:

* Shoham, Leyton-Brown. Multiagent Systems.

* Nisan, Roughgarden, Tardos, Vazirani. Algorithmic Game Theory.

* Cramton, Shoham, Steinberg, Smith. Combinatorial Auctions.

For the traditional economic theory of asymmetric information among economic agents:

* Bikchandani, Riley and Hirshleifer. The Analytics of Uncertainty and Information.